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Abstract The aim of this study was to evaluate safety and efficacy of a poly-L-lactic acid (PLLA)-coated magnesium (Mg)-Dysprosium (Dy) membrane in guided bone regeneration (GBR) using a rabbit calvarium model. The microstructure of the Mg-Dy membrane surface and thickness of the PLLA coating were examined. In vitro degradation and cytotoxicity test was conducted. The in vivo study used 24 white male rabbits with two 8 mm-diameter defects created on the calvaria; 12 defects were randomly assigned per group: (1) Negative control, (2) positive control, (3) uncoated Mg, and (4) PLLA-coated Mg group. Specimens were harvested at 4, 8, and 12 weeks postoperatively for radiological, histological, and histomorphometric analyses. The PLLA-coated Mg-Dy membrane showed a low degree of degradation, indicating that the coating exerted a protective effect. In the cytotoxicity test, no deformed or degenerated cells were observed. In the in vivo study, radiographic and histomorphometric analyses indicated favorable new bone formation and maintenance of the graft material for PLLA-coated Mg group. PLLA-coated Mg group, compared to the uncoated counterpart, restored the bony contour more completely, without inducing significant inflammatory response. Our results support the safety and efficacy of PLLA-coated Mg-Dy membranes for GBR both in vitro and in vivo.

BACKGROUND: Scholars at home and abroad consider New Zealand rabbits to be an ideal model animal because of the similar anatomical morphology of the lumbar spine to that of the human lumbar spine. There is a lack of systematic comparison of different ways to establish rabbit intervertebral disc degeneration models under X-ray guidance. OBJECTIVE: To establish a rabbit model of lumbar disc degeneration using X-ray guided acupuncture, end-plate injection and combined method, and to compare the modeling effects of these three methods. METHODS: Eighteen 6-month-old New Zealand white rabbits were randomly selected and divided into four groups: acupuncture group, endplate injection group, combined group and blank control group. In the acupuncture group, three consecutive segments of the intervertebral discs (L2/3, L3/4, L4/5) were needled and modeled; in the endplate injection group, 50 μL of anhydrous ethanol was injected at a single point on the endplates of the three consecutive segmental discs; in the combined group, three consecutive segmental intervertebral discs were needled and injected with 50 μL of anhydrous ethanol at four azimuthal points on the endplates of the corresponding segmental discs; and the blank control group received no interventions. X-ray examination was performed to measure the disc height index at 2, 4, and 8 weeks after surgery. The intervertebral disc tissues were then taken for anatomical observation and pathological examination. RESULTS AND CONCLUSION: (1) Anatomical examination showed that fibrous annulus rupture, nucleus pulposus degeneration, and total disc structure disorder were the main manifestation in the acupuncture group, endplate injection group, and combined group, respectively. (2) X-ray examination showed that the disc height index showed the most obvious reduction in the acupuncture group at 2 weeks after operation, significant reductions in the endplate injection group at 2 and 4 weeks after operation, and significant reductions in the combined group at 2, 4, and 8 weeks after operation. (3) Pathological examination showed that the fibrous ring structure was damaged and the inner annulus fibrosus protruded inward in the acupuncture group; endplate fissure, disordered arrangement and nucleus loss were observed in the endplate injection group; total disc structure disorder with the nucleus pulposus losing water and shrinking and no obvious border with the broken annulus fibrosus was found in the combined group. To conclude, acupuncture, endplate injection and the modified endplate injection method can establish the rabbit intervertebral disc degeneration model. Compared with the single method, the modified endplate injection method can greatly accelerate and aggravate the degeneration of the intervertebral disc, and can effectively shorten the experiment period. [ABSTRACT FROM AUTHOR]

OBJECTIVE To evaluate selected gastrointestinal side effects of high-concentration buprenorphine (HCB) in healthy rabbits. ANIMALS 10 healthy New Zealand White rabbits ranging in body weight between 3.0 and 3.8 kg. METHODS Eight, 6-month-old, New Zealand White rabbits received a single injection of HCB SC (0.24 mg/kg). The rabbits were previously randomized to receive SC and oral saline as a control. Two rabbits received saline for the purpose of blinding the outcome assessors. Food and water consumption, fecal and urine production, and fecal pellet number were recorded for all rabbits before HCB administration and the 3 days postinjection. RESULTS A clinically and statistically significant decrease in food and water consumption was observed in rabbits receiving an injection of HCB, compared to rabbits receiving saline. In the 24 hours after injection, HCB-treated rabbits consumed a median of 17 g of food (range, 0 to 82 g), while saline-treated rabbits consumed 122 g of food (31 to 181 g). Rabbits receiving HCB injections also produced significantly less feces both in terms of pellet numbers and overall quantity, along with decreased urine production. CLINICAL RELEVANCE A single administration of HCB has a clinically significant impact on multiple physiological functions in healthy rabbits. Administration of this drug could potentially worsen clinical signs of anorexia and decrease defecation in healthy rabbits. The effects of HCB on diseased or painful rabbits are not yet known. [ABSTRACT FROM AUTHOR]

The role of iron in promoting atherosclerosis, and hence the cardiovascular, neurodegenerative and other diseases that result from atherosclerosis, has been fiercely controversial. Many studies have been carried out on various rodent models of atherosclerosis, especially on apoE -knockout (apoE −/− ) mice, which develop atherosclerosis more readily than normal mice. These apoE −/− mouse studies generally support a role for iron in atherosclerosis development, although there are conflicting results. The purpose of the current article is to describe studies on another animal model that is not genetically manipulated; New Zealand White (NZW) rabbits fed a high-cholesterol diet. This may be a better model than the apoE −/− mice for human atherosclerosis, although it has been given much less attention. Studies on NZW rabbits support the view that iron promotes atherosclerosis, although some uncertainties remain, which need to be resolved by further experimentation. [Display omitted] [ABSTRACT FROM AUTHOR]

Bone defects are common consequences of bone trauma. The application of biomaterials as tissue scaffolds combined with oxygenating agents, as bone regeneration promoters, is an interesting strategy to improve bone repair. The present study aimed to investigate the potential of a temperature-sensitive hydrogel containing 1-bromoheptafluorooctane in repairing rabbit bone defects and its possible mechanism of action. Bone defects were surgically created in the femoral condylar of New Zealand White rabbits. The animals were divided into three groups: A) treated with the temperature-sensitive hydrogel containing 1-bromoheptafluorooctane with oxygen release; B) treated with the temperature-sensitive hydrogel containing 1-bromoheptafluorooctane without oxygen release; and C) received no treatments. At four and 12 weeks post-operation, the specimens from all groups were collected. The new bone formation was studied by morphological observation, X-ray, Micro-CT, Masson’s trichrome, and CD31 immunohistochemical staining. At 12 weeks post-operation, the bone defects were completely healed in groups A and B, while a major bone defect was still present in group C. Micro-CT showed that TMD, BVF, Tb.Th and Tb.N in group A were significantly higher compared to the other groups at each time point post-operation. The SMI value of group A showed a significant difference from the other groups at 12 weeks post-operation. The number of micro-vessels in group A was significantly higher compared to the other groups at four and 12 weeks post-operation. The oxygenating temperature-sensitive hydrogel containing 1-bromoheptafluorooctane could effectively promote new bone formation while increasing tissue vascularization, highlighting a good clinical application prospect.

Female rabbits from the age of 9 weeks till age of maturity were reared in two separate groups under long (16L: 8D) and short (control) (12L: 12D) photoperiods. The primary follicles were characterized by the presence of single layer of cuboidal granulosa cells surrounding the oocyte. Does reared under long photoperiod recorded greater primary follicle and oocyte diameter at 15 weeks of age as compared to those reared in short photoperiod. At pre-pubertal age the serum concentration of FSH was greater in long photoperiod animals as compared to those of short photoperiod animals. [ABSTRACT FROM AUTHOR]

AIM: To investigate the distribution of conjunctival lymphatic vessels in New Zealand white rabbits and its relationship with age.METHODS: Subconjunctival trypan blue was injected in four quadrants(nasal, superior, temporal, and inferior)and recorded videos. The number of lymphatic outflow pathways arising from the blebs was counted. The difference in the number of lymphatic outflow pathways across the quadrants of each group was tested by single-factor analysis of variance. Paired t-test was used to compare the differences in the number of lymphatic outflow pathways in the same rabbit quadrants across different ages.RESULTS: In New Zealand white rabbits, thick annular lymphatic vessels were mainly distributed near the limbus part of the conjunctiva. The single collecting lymphatic vessels were primarily distributed in the peripheral parts. Although the lymphatic vessels of juvenile rabbits have fewer branches, the number of lymphatic vessels in the different quadrants was no significant difference in each group(all P>0.05)and was no difference between the two age groups(all P >0.05).CONCLUSION:The lymphatic vessels were abundant in rabbit conjunctiva. The number of lymphatic vessels in each quadrant and between two age groups had no significant difference.

• Overexpression of lncRNA TCONS_02443383 upregulates PPAR signaling pathways in AS. • lncRNA TCONS_02443383 enhances genes related to cell adhesion in atherosclerosis. • RNA-seq and qRT-PCR validate lncRNA TCONS_02443383′s role in AS regulation. • Lentiviral plasmids upregulate lncRNA TCONS_02443383, impacting AS development. In this study, we performed RNA sequencing (RNA-seq) on the abdominal aorta tissue of New Zealand rabbits and investigated the potential association of lncRNA TCONS_02443383 with the development of AS through bioinformatics analysis of the sequencing data. The obtained results were further validated using quantitative real-time polymerase chain reaction (qRT-PCR). We induced an AS model in New Zealand rabbits by causing balloon injury to the abdominal aorta vascular wall and administering a high-fat diet. We then upregulated the expression level of the lncRNA TCONS_02443383 by injecting lentiviral plasmids through the ear vein. RNA sequencing (RNA-seq) was performed on the abdominal aorta tissues. We conducted Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway and Gene Ontology (GO) analyses. The overexpression of the lncRNA TCONS_02443383 led to an upregulation of peroxisome proliferator-activated receptor (PPAR) signaling pathways as well as genes related to cell adhesion. The overexpression of the lncRNA TCONS_02443383 can inhibit the occurrence and development of AS by upregulating peroxisome proliferator-activated receptor (PPAR) signaling pathways and genes related to cell adhesion. [ABSTRACT FROM AUTHOR]

Background The deliberate use of Bacillus anthracis spores is believed by the US government to be a high bioweapons threat. The first line of defense following potential exposure to B. anthracis spores would be postexposure prophylaxis with antimicrobials that have activity against B. anthracis. Additional therapies to address the effects of toxins may be needed in systemically ill individuals. Over the last 2 decades, the United States government (USG) collaborated with the private sector to develop, test, and stockpile 3 antitoxins: anthrax immunoglobulin intravenous (AIGIV), raxibacumab, and obiltoxaximab. All 3 products target protective antigen, a protein factor common to the 2 exotoxins released by B. anthracis , and hamper or block the toxins' effects and prevent or reduce pathogenesis. These antitoxins were approved for licensure by the United States Food and Drug Administration based on animal efficacy studies compared to placebo. Methods We describe USG-sponsored pre- and postlicensure studies that compared efficacy of 3 antitoxins in a New Zealand White rabbit model of inhalation anthrax; survival following a lethal aerosolized dose of B. anthracis spores was the key measure of effectiveness. To model therapeutic intervention, intravenous treatments were started following onset of antigenemia. Results In pre- and postlicensure studies, all 3 antitoxins were superior to placebo; in the postlicensure study, raxibacumab and obiltoxaximab were superior to AIGIV, but neither was superior to the other. Conclusions These data illustrate the relative therapeutic benefit of the 3 antitoxins and provide a rationale to prioritize their deployment. [ABSTRACT FROM AUTHOR]

Diarrhoeal diseases are the second leading cause of death for children under 5 years old in 69 low- and middle-income countries, with an annual economic burden of US$ 4 billion and over 525,000 lives lost. Cholera and enterotoxigenic Escherichia coli (ETEC) traveller's diarrhoea are major diarrhoeal diseases caused by Vibrio cholerae (O1 and O139 serogroups) and ETEC, which have similar pathogeneses and can co-infect. There is no exclusive vaccine for ETEC, but cholera vaccines containing the cholera toxin B (CT-B) component offer short-term cross-protection. However, licensed oral cholera vaccines are expensive due to cold-chain supplies and the need for multiple doses. A cost-effective, dual-protection, live, cold-chain-free vaccine is, therefore, required for vaccination campaigns in low-resource settings, and MyChol - a prototype cold-chain-free live attenuated cholera vaccine, targeting V. cholerae O139 and ETEC H10407 - was developed in this context. The vaccine was evaluated in three animal models (Sprague Dawley [SD] rats, BALB/c mice and New Zealand white rabbits) for safety, colonisation capacity, reactogenicity and immunogenicity against challenge strains. In suckling mice, MyChol displayed high colonisation potential compared to unformulated VCUSM14P (the vaccine candidate) and wild-type O139. In the acute toxicity assessment, the SD rats with the highest MyChol dose (1 × 10 7 colony-forming unit [CFU]/kg) demonstrated no adverse effects or mortality. Mice vaccinated with MyChol exhibited elevated antibody levels, including anti-CT, anti-heat-labile enterotoxin (LT), anti-CT-B and anti-LT-B. Anti-CT antibodies neutralised LT toxin in ETEC H10407 in challenge studies and cross-protected against ETEC H10407 in both mice and rabbits, preventing weight loss and diarrhoea. Ileal loop experiments in rabbits and BALB/c mice showed no reactogenicity. This review, based on our previous research, therefore provides valuable insights into improving the selection of animal models to advance preclinical evaluations of diarrhoeal vaccines., Competing Interests: Conflicts of Interest: None., (© Penerbit Universiti Sains Malaysia, 2024.)

Rabbit haemorrhagic disease virus (RHDV) is associated with high morbidity and mortality in the European rabbit (Oryctolagus cuniculus). In 2010, a genetically distinct RHDV named RHDV2 emerged in Europe and spread to many other regions, including North America in 2016. Prior to this study it was unknown if eastern cottontails (ECT(s); Sylvilagus floridanus), one of the most common wild lagomorphs in the United States, were susceptible to RHDV2. In this study, 10 wild‐caught ECTs and 10 New Zealand white rabbits (NZWR(s); O. cuniculus) were each inoculated orally with either RHDV (RHDVa/GI.1a; n = 5 per species) or RHDV2 (a recombinant GI.1bP‐GI.2; n = 5 per species) and monitored for the development of disease. Three of the five ECTs that were infected with RHDV2 developed disease consistent with RHD and died at 4 and 6 days post‐inoculation (DPI). The RHDV major capsid protein/antigen (VP60) was detected in the livers of three ECTs infected with RHDV2, but none was detected in the ECTs infected with RHDV. Additionally, RHD viral RNA was detected in the liver, spleen, intestine and blood of ECTs infected with RHDV2, but not in the ECTs infected with RHDV. RHD viral RNA was detected in urine, oral swabs and rectal swabs in at least two of five ECTs infected with RHDV2. One ECT inoculated with RHDV2 seroconverted and developed a high antibody titre by the end of the experimental period (21 DPI). ECTs inoculated with the classic RHDV did not seroconvert. In comparison, NZWRs inoculated with RHDV2 exhibited high mortality (five of five) at 2 DPI and four of five NZWRs inoculated with RHDV either died or were euthanized at 2 DPI indicating both of these viruses were highly pathogenic to this species. This experiment indicates that ECTs are susceptible to RHDV2 and can shed viral RNA, thereby suggesting this species could be involved in the epidemiology of this virus. [ABSTRACT FROM AUTHOR]

This study was aimed to compare the eff ect of 1% atropine, 1% cyclopentolate, 0.5% tropicamide, and 10% phenylephrine eye drops on intraocular pressure (IOP) and central corneal thickness (CCT) in New Zealand White rabbits. Adult male, eight, New Zealand White rabbits were randomly received each of four mydriatic eye drops separately on left eye at a one-week washout period. Each rabbit received all of five diff erent treatments (sterile saline solution, four mydriatic drugs) on the left eye, whereas no measurements were performed on the right eyes during the experiment. The IOP and CCT recordings of rabbits were performed until the pupil returned to normal diameter. The mean CCT values of sterile saline, 1% atropine, 0.5% tropicamide, 1% cyclopentolate, and 10% phenylephrine were 370±15, 368±17, 372±15, 364±18, and 360±17 μm, respectively, and no statistically significant diff erences (P>0.05) were observed among groups. The mean IOP values of control (sterile saline), 1% atropine, 0.5 % tropicamide, 1% cyclopentolate, and 10% phenylephrine as, 9.7±2.1, 10.4±1.8, 10.3±2.1, 11.0±2.1, and 10±1.8 mmHg, respectively, and these were not statistically significant among groups (P>0.05). In conclusion, topical 1% atropine, 0.5% tropicamide 1% cyclopentolate, and 10% phenylephrine do not have significantly eff ect on IOP and CCT in New Zealand white rabbits.

Background and Aim: Adipose tissue-derived stromal vascular fraction (SVF) contains a heterogeneous cell population comprising multipotent adipose-derived stem cells. Regenerative therapy using adipose-derived SVF has broad applications in bone tissue engineering due to the superior osteogenic potential of SVF. This study was designed to standardize and characterize adipose-derived SVF obtained from New Zealand white rabbits for bone tissue engineering and other potential applications. Materials and Methods: Ten skeletally mature and clinically healthy adult New Zealand white rabbits were used in this study. The SVF was prepared using surgically resected interscapular adipose tissue following enzymatic digestion with 0.1% collagenase type I solution. The SVF pellet obtained after the final centrifugation step was suspended in a 0.5 mL control solution to obtain ready-to-use adipose-derived SVF. The freshly prepared SVF was characterized based on the total SVF cell count and cell yield per gram of adipose tissue. The SVF cells were enumerated using a hemocytometer. Results: Interscapular adipose tissue depots are ideal for preparing autologous adipose-derived SVF due to the ease of access. The interscapular adipose-derived SVF prepared by enzymatic digestion had an average cell yield of 3.15±0.09×106 cells/g adipose tissue. Freshly prepared SVF had a total cell count of 3.15±0.09×104 cells/μL. Conclusion: The enzymatic digestion of adipose tissue using 0.1% collagenase resulted in better cell yield per gram than methods previously reported in rabbits. The use of adipose-derived SVF can preclude the requirement for an additional culture period. In addition, it may also reduce the risk of extensive cell contamination, which makes it a safe and cost-effective strategy for bone tissue engineering applications.

Background: The selection and validation of stably expressed reference genes is key for accurately quantifying the mRNA abundance of genes under different treatments. In the rabbit model of fasting caecotrophy, reports about the selection of stable reference genes are not available. Methods and results: This study aims to screen suitable reference genes in different tissues (including uterus, cecum, and liver) of rabbits between control and fasting caecotrophy groups. RT-qPCR was used to analyze the expression levels of eight commonly used reference genes (including GAPDH, 18S rRNA, B2M, CYP, HPRT1, β-actin, H2afz, Ywhaz), and RefFinder (including geNorm, NormFinder, and BestKeeper) was used to analyze the expression stability of these reference genes. Our results showed that the most stable reference genes were different in different tissues and treatments. In the control and fasting caecotrophy groups, CYP, GAPDH and HPRT1 were proven to be the top stable reference genes in the uterus, cecum, and liver tissues, respectively. GAPDH and Ywhaz were proven to be the top two stable reference genes among uterus, cecum, and liver in both control and fasting caecotrophy groups. Conclusions: Our results indicated that the combined analysis of three or more reference genes (GAPDH, HPRT1, and Ywhaz) are recommended to be used for RT-qPCR normalization in the rabbit model of fasting caecotrophy, and that GAPDH is a better choice than the other reference genes for normalizing the relative expression of target genes in different tissues of fasting caecotrophy rabbits. [ABSTRACT FROM AUTHOR]

The present study investigated the gross and histological description of the rabbit testes with the histomorphometrical indices of the testes. Four male intact New Zealand white rabbits were procured with average weight of 1.35 ±0.13kg and were housed in individual cages at the animal house of the Faculty of Veterinary Medicine, University of Ibadan. Gross pictures and measurements of the testes were recorded while the testes tissues were processed for histology and histometric assessment of seminiferous tubules. Results showed that gross measurement of the right testis were about 2.88cm in length and 0.61cm in breadth. The measurement of the left testis were about 2.65cm and 0.65cm. The average histomorphometrical readings for the seminiferous tubular diameter and seminiferous epithelial height were 265.84µm and 204.09µm respectively. The histological slides revealed normal testicular architecture in the rabbits.

A total of twenty four unsexed New Zealand White (NZW) rabbits, weaned at 5 weeks of age, were observed to assess the impacts of some environmental stressors like stocking density (SD) and external parasite infestation (mite) on the growth performance and some blood biochemical parameters of this growing rabbits and assess the use of Oregano Essential Oil (OEO) supplementation as an antistressor for the rabbit intensification and mite infestation problems. NZW rabbits were housed in wire cages (45 cm x 45 cm x35 cm) in groups of 2 rabbits cage-1 (low stocking density; LSD) and 4 rabbits cage-1 (high stocking density; HSD). For the two densities, NZW rabbits were fed three diets with variable OEO levels and experimentally infested with P. cuniculi for 7 weeks by the following manner, (T1) group was the control group that has 0.0 OEO level kg-1 diet without mite infestations, (T2) and (T3) group were supplemented with 200 mg OEO kg-1 diet but only (T3) group was experimentally infested with mites, while the last treatment (T4) was experimentally infested with mites and supplemented with 400 mg OEO kg-1 diet. Finally, the current study found that a low dose of OEO-based feed had a favorable influence on the growth performance of NZW rabbits kept at LSD, with apparent benefits on antioxidant defense and innate immunity status. Our results also revealed that feed conversion ratio in rabbits provided with phytogenic supplemented diets had significantly lower values than in rabbits fed other treatments, indicating that phytogenics can promote growth. As a result, the practical consequences of phytogenic inclusion in rabbit feeds include the potential to improve rabbit growth performance and feed utilization. This would allow for faster rabbit growth, which would result in increased production time at optimal density while avoiding rabbits' parasitic infestations with mite. In conclusion, the findings of this study revealed that adding OEO in a dose of 200 mg kg-1 diet enhanced feed utilisation, rabbit somatic growth and ameliorating intensification and mite infestation stress effects on NZW rabbits. [ABSTRACT FROM AUTHOR]

The purpose of the study was to investigate the effects of dietary 1% Rumanol ML supplementation on meat quality. A total of 50 weaned New Zealand White rabbits were employed, divided in two groups: experimental and control (2 x 25 animals). Experimental rabbits were fed pelleted feed supplemented with 1% Rumanol ML, and controls: only pelleted feed. When all animals attained a Minimum live weight of 3.00 kg, ten male rabbits from each group were slaughtered. Preslaughter live weight, hot and cold carcass weight and slaughter yield were determined. Technological properties and chemical composition of Мusculus Longissimus thoracis et lumborum were evaluated.It was demonstrated that experimental animals had insignificantly higher slaughter yield and higher cooling loss compared to controls. Meat pH24 values of supplemented animals were higher than respective values of controls (Р≤0.05). Meat water holding capacities (WHC) were higher while cooking loss – lower in experimental group (Р≤0.001). There were no relevant between-group differences with regard to the chemical composition of tested meat samples. [ABSTRACT FROM AUTHOR]

This study was aimed to compare the effect of 1% atropine, 1% cyclopentolate, 0.5% tropicamide, and 10% phenylephrine eye drops on intraocular pressure (IOP) and central corneal thickness (CCT) in New Zealand White rabbits. Adult male, eight, New Zealand White rabbits were randomly received each of four mydriatic eye drops separately on left eye at a one-week washout period. Each rabbit received all of five different treatments (sterile saline solution, four mydriatic drugs) on the left eye, whereas no measurements were performed on the right eyes during the experiment. The IOP and CCT recordings of rabbits were performed until the pupil returned to normal diameter. The mean CCT values of sterile saline, 1% atropine, 0.5% tropicamide, 1% cyclopentolate, and 10% phenylephrine were 370±15, 368±17, 372±15, 364±18, and 360±17 μm, respectively, and no statistically significant differences (P>0.05) were observed among groups. The mean IOP values of control (sterile saline), 1% atropine, 0.5% tropicamide, 1% cyclopentolate, and 10% phenylephrine as, 9.7±2.1, 10.4±1.8, 10.3±2.1, 11.0±2.1, and 10±1.8 mmHg, respectively, and these were not statistically significant among groups (P>0.05). In conclusion, topical 1% atropine, 0.5% tropicamide 1% cyclopentolate, and 10% phenylephrine do not have significantly effect on IOP and CCT in New Zealand white rabbits. [ABSTRACT FROM AUTHOR]

ObjectivesEvaluate safety of autogenous engineered septal neocartilage grafts.Compare properties of implanted grafts versus in vitro controls.Study designProspective, basic science.SettingResearch laboratory.MethodsConstructs were fabricated from septal cartilage and serum harvested from adult rabbits and then cultured in vitro or implanted on the nasal dorsum as autogenous grafts for 30 or 60 days. Rabbits were monitored for local and systemic complications. Histological, biochemical and biomechanical properties of implanted and in vitro constructs were evaluated and compared.ResultsNo systemic or serious local complications were observed. After 30 and 60 days, implanted constructs contained more DNA (p

Background and Aim: Adipose tissue-derived stromal vascular fraction (SVF) contains a heterogeneous cell population comprising multipotent adipose-derived stem cells. Regenerative therapy using adipose-derived SVF has broad applications in bone tissue engineering due to the superior osteogenic potential of SVF. This study was designed to standardize and characterize adipose-derived SVF obtained from New Zealand white rabbits for bone tissue engineering and other potential applications. Materials and Methods: Ten skeletally mature and clinically healthy adult New Zealand white rabbits were used in this study. The SVF was prepared using surgically resected interscapular adipose tissue following enzymatic digestion with 0.1% collagenase type I solution. The SVF pellet obtained after the final centrifugation step was suspended in a 0.5 mL control solution to obtain ready-to-use adipose-derived SVF. The freshly prepared SVF was characterized based on the total SVF cell count and cell yield per gram of adipose tissue. The SVF cells were enumerated using a hemocytometer. Results: Interscapular adipose tissue depots are ideal for preparing autologous adipose-derived SVF due to the ease of access. The interscapular adipose-derived SVF prepared by enzymatic digestion had an average cell yield of 3.15±0.09×106 cells/g adipose tissue. Freshly prepared SVF had a total cell count of 3.15±0.09×104 cells/µL. Conclusion: The enzymatic digestion of adipose tissue using 0.1% collagenase resulted in better cell yield per gram than methods previously reported in rabbits. The use of adipose-derived SVF can preclude the requirement for an additional culture period. In addition, it may also reduce the risk of extensive cell contamination, which makes it a safe and costeffective strategy for bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

BACKGROUND: Many methods have been developed to establisha rabbit VX2 tumor model, but the reliability of each method has not been explored. In order to develop a reliable method, we made some improvements based on the existing methods. OBJECTIVE: To investigate the reliability of rabbit VX2 tumor tissue block implantation and cell suspension via modified and traditional implantation to make the rabbit tibia VX2 tumor model.METHODS: Forty healthy adult New Zealand white rabbits were randomly divided into two groups. Group A was treated with tissue block implantation for tibia VX2 tumor modeling, and group B was treated with cell suspension for tibia VX2 tumor modeling. Modified and traditional implantation was performed on the left and right tibia of the experimental animals, respectively. One hour after successful modeling, ultrasound examination of the puncture site was performed to determine whether there is hematoma. All experimental animals were sacrificed at 3 weeks. X-ray examination of the bilateral tibia was performed to confirm the tumor growth range. Tumor tissue and soft tissue around the puncture site were taken for general and pathological observation to compare the size of the tumor and identify whether there is tumor cell metastasis.RESULTS AND CONCLUSION: One rabbit died in the tissue block group, and all the experimental animals in the cell suspension group survived. X-ray examination indicated the tumors in the tissue block group invaded the cortex, but the tumors in the cell suspension group did not invade the cortex. Gross observation revealed that the tumor volume of the tissue block group was greater than that of the cell suspension group. In the tissue block group, there were one and seven cases of hematoma around the puncture site at 1 hour after modified and traditional implantation, respectively. In the cell suspension group, there were two and nine cases of hematoma around the puncture site at 1 hour after modified and traditional implantation, respectively. Pathological examination showed that local tumor invasion was found in 1 and 8 cases in the tissue block group as well as in 2 and 11 cases in the cell suspension group at 3 months after modified and traditional implantation, respectively. Our findings indicate that the tissue block implantation method is easier and more convenient than the cell suspension method for making rabbit VX2 bone tumors, and the tumor invasion rate of the tissue block implantation method is lower than that of the cell suspension method. Improved tissue block implantation can effectively reduce the tumor invasion rate during modeling. [ABSTRACT FROM AUTHOR]

The present study investigated the gross and histological description of the rabbit testes with the histomorphometrical indices of the testes. Four male intact New Zealand white rabbits were procured with average weight of 1.35 ±0.13kg and were housed in individual cages at the animal house of the Faculty of Veterinary Medicine, University of Ibadan. Gross pictures and measurements of the testes were recorded while the testes tissues were processed for histology and histometric assessment of seminiferous tubules. Results showed that gross measurement of the right testis were about 2.88cm in length and 0.61cm in breadth. The measurement of the left testis were about 2.65cm and 0.65cm. The average histomorphometrical readings for the seminiferous tubular diameter and seminiferous epithelial height were 265.84μm and 204.09μm respectively. The histological slides revealed normal testicular architecture in the rabbits. [ABSTRACT FROM AUTHOR]

Background: The aim of the study was to estimate the volume values of the cranial cavity and nasal cavity structures and to compare the efficiency of manual segmentation of three-dimensional reconstruction and Cavalieri's principle (CP) methodologies.Materials and Methods: Volume values of the cranial cavity, maxillary sinus (MS), dorsal conchal sinus (DCS), dorsal nasal meatus (DNM), middle nasal meatus (MNM), ventral nasal meatus (VNM), ventral nasal concha (VNC), middle nasal concha (MNC) and nasal vestibule (NV) were estimated with manual segmentation and CP from micro-computed tomography images in 5 male New Zealand white rabbits. Volume measurements and elapsed time were compared with each other. Three-dimensional reconstruction models of nasal and cranial cavity structures were created.Results: There was a statistically significant difference between methods of the MS, DCS, DNM, MNM, VNM, VNC, and MNC volume measurements. Additionally, there was a statistically significant difference between the volumetric analysis time period of the methods and CP was found much shorter than manual segmentation.Conclusions: Realistic results were achieved in a short time with the CP among the stereology methods. It is thought that these image and quantitative data results can be used for modelling, toxicology and pathology studies such as acute and chronić rhinitis or rhino sinusitis as well as a good understanding of the relationship of the anatomical structures in the nasal cavity. [ABSTRACT FROM AUTHOR]

Cecotrophy is a special behaviour of rabbits. Eating soft faeces can improve feed efficiency and maintain gut flora in rabbits. In our previous study, we found that fasting from soft faeces significantly reduced growth rate and total cholesterol (TC) in New Zealand white rabbits (NZW rabbits), thereby resulting in lower values for body weight and fat deposition in the soft faeces fasting group than in the control group. However, it has not been demonstrated whether cecotrophy by NZW rabbits can regulate lipid metabolism by changing the diversity of caecal microorganisms. In this study, thirty‐six 28‐day‐old weaned NZW female rabbits were randomly divided into two groups (the soft faeces fasting group and the control group) and fed to 90 days. Rabbits in the experimental group were treated with an Elizabeth circle to prevent them from eating their soft faeces. Then, the caecal contents of three rabbits from the soft faeces fasting group and three rabbits from the control group were collected for metagenomic sequencing. We found that the abundance of Bacteroides increased, while Ruminococcus decreased, compared with the control group after fasting from soft faeces. Relative abundance was depressed for genes related to metabolic pathways such as ascorbate and aldarate metabolism, riboflavin metabolism and bile secretion. Moreover, there was a general correlation between variation in microbial diversity and fat deposition. Bacteroides affects body weight and TC by participating in the riboflavin metabolism pathway. By investigating the effect of cecotrophy on caecal microorganisms of rabbits, we identified the key microorganisms that regulate the rapid growth performance of NZW rabbits, which may provide useful reference for the future research and development of microecological preparations for NZW rabbits. [ABSTRACT FROM AUTHOR]

Introduction and hypothesis: New Zealand white rabbits are an inexpensive large-animal model. This study explored the rabbit as a model for mesh-augmented colpopexy using the intra-abdominal vagina. We hypothesized that polypropylene mesh would negatively impact rabbit vaginal smooth muscle (VSM) morphology and contractile function, similar to the nonhuman primate (NHP)—the established model for prolapse mesh evaluation. Methods: Restorelle was implanted onto the vagina of ten rabbits via lumbar colpopexy after a hysterectomy. Ten rabbits served as sham. Twelve weeks post-implantation, the vagina was excised and VSM morphology and vaginal contractility were assessed. Outcome measures were compared using independent samples t and Mann-Whitney U tests with a Bonferroni correction, where appropriate. Results from the rabbits were compared with published NHP data. Results: Animals had similar age, parity and BMI. VSM was 18% thinner after Restorelle implantation, P = 0.027. Vaginal contractility was 43% decreased in response to 120 mM KCl (P = 0.003), similar to the 46% reduction observed in the NHP vagina implanted with Restorelle (P = 0.027). Three meshes wrinkled in vivo, resulting in dramatic thinning of the underlying vagina in the area of the mesh causing a mesh exposure. Conclusions: Polypropylene mesh negatively impacts VSM morphology and vaginal contractility in the rabbit, similar to the NHP, suggesting that the rabbit may serve as an alternative large-animal model. The vaginal thinning and appearance of a mesh exposure in the area of a mesh wrinkle suggest the rabbit may also serve as a model for understanding the pathophysiology of mesh exposure. [ABSTRACT FROM AUTHOR]

There are several animal models routinely used for study of the spinal fusion process and animal selection largely depends on the scientific question to be answered. This review outlines the advantages and disadvantages of various animal models used to study spinal fusion and describes the New Zealand White (NSW) rabbit which is the most popular preclinical model to study spinal fusion. We outline critical steps required in planning and performing spinal fusion surgery in this model. This includes determination of the required animal number to obtain statistical significance, an outline of appropriate technique for posterolateral fusion and other components of completing a study. As advances in drug delivery move forward and our understanding of the cascade of gene expression occurring during the fusion process grows, performing and interpreting preclinical animal models will be vital to validating new therapies to enhance spinal fusion.

Species-dependent differences in relative incidence of spontaneous variations and malformations should be considered in the assessment of the translational value of reproductive and developmental safety assessments. The objective of this evaluation was to compare litter parameters and the frequency of external, visceral, and skeletal malformations and variations across species in the Sprague-Dawley rat, New Zealand White rabbit, and Göttingen minipig and to determine whether notable differences exist. Pregnant female rats (n = 824), rabbits (n = 540), and minipigs (n = 70) from vehicle control groups were included in the analysis, equating to 10,749 rat, 5,073 rabbit, and 378 pig fetuses collected at term by cesarean delivery. Preimplantation loss was more frequent than postimplantation loss in the rat and rabbit, whereas the opposite was observed in the minipig. Several external and visceral malformations and variations such as domed head, bent tail, abdominal edema, and anal atresia were observed in all 3 species. Visceral malformations of the heart and major blood vessels were remarkably more frequent in the minipig and rabbit, respectively; ventricular and atrium septum defects were observed in 1.9% and 2.1%, respectively, for the minipig fetuses, whereas they were observed in equal or less than 0.02% among the rat and rabbit fetuses evaluated in this study. Understanding species-dependent differences in spontaneous variations and malformations can be useful for the interpretation of embryo–fetal development study results. The current analysis identified relevant differences between commonly used species in reproductive toxicology with potential implications for data assessment. [ABSTRACT FROM AUTHOR]

Objective • To observe the effect of thcrmosensitive hydroxybulyl chitosan (HBC) hydrogel in the prevention of intrauterine adhesion in New Zealand white rabbits. Methods • Eighteen female New Zealand rabbits were randomly divided into 3 groups, normal control group, model group and HBC group. Normal control group underwent sham operatioiL The models of intrauterine adhesion were constructed by both mechanical damage and infection in model group and HBC group. In HBC group, 2 mL 1.5% thermosensitive HBC hydrogel was injected into ihe uterine cavity immediately after injury. Two rabbits were killed in each group 1 week, 2 weeks and 4 weeks after operatioii, respectively. The bilateral uterine tissues were collected. The endometrial morphology and quantity of glands were observed by hematoxylin-eosin staining，The area of fibrosis in endometrium was measured by Masson staining. Results• One week after operation, compared with normal control group, the columnar epithelial cells of endometrium gradually disappeared and the ratio of endometrial fibrosis area increased significantly in the other two groups. The number of glands also decreased. After 2 weeks, intrauterine adhesion was observed in model gro叩，and the ratio of endometrial fibrosis area continuGd increasing，and the number of glands decreased further. However, in HBC group, there was no residual hydrogel in the uterine cavity, and the ratio of endometrial fibrosis area decreased and the number of glands increased. After 4 weeks, there was a recovery of columnar epithelium cells，the ratio of endometrial fibrosis area, and the number of glands in HBC group, which returned to the normal level Conclusion•Thermosensitive HBC hydrogel can effectively prevent intrauterine adhesion in New Zealand white rabbits. [ABSTRACT FROM AUTHOR]

Background: Gastrointestinal (GI) endocrine cells produce many GI hormones that perform various physiological functions of the digestive system. Aims: We aimed to investigate the presence and distribution of immunoreactive (IR) endocrine cells to glucagon, somatostatin, cholecystokinin-8 (CCK-8), serotonin, secretin and histamine in the stomach of adult male New Zealand White rabbit (Oryctolagus cuniculus). Methods: For immunohistochemical staining, peroxidase anti-peroxidase (PAP) method was applied to stomach samples. Results: Glucagon-IR cells of closed- and open type were found throughout all the stomach parts examined. Somatostatin-IR cells of closed- and open type in the cardiac and oxyntic glands were localized to deep portions of foveola gastrica. CCK-8 IR cells that were not observed in the cardia and fundus were mostly localized to the glands and lamina epithelialis in the pyloric part near the duodenum. Oval-shaped open and closed type serotonin-IR cells were mostly dispersed throughout the fundic and pyloric glands. Secretin-IR cells were rare in the pyloric and cardiac region although they were not observed in the fundic glands. Histamine-IR cells were rarely found in the cardia, fundus and pylorus. Conclusion: Our findings show that glucagon, histamine, somatostatin, secretin and serotonin might be produced by all the stomach regions while pyloric region had only CCK-8 IR. These distribution patterns also provide further evidence of species-specific differences, which might be important from the evolutionary aspect of the digestive tract in relation to evolutional niches and nutrient resources. [ABSTRACT FROM AUTHOR]

Bone defects are common consequences of bone trauma. The application of biomaterials as tissue scaffolds combined with oxygenating agents, as bone regeneration promoters, is an interesting strategy to improve bone repair. The present study aimed to investigate the potential of a temperature-sensitive hydrogel containing 1-bromoheptafluorooctane in repairing rabbit bone defects and its possible mechanism of action. Bone defects were surgically created in the femoral condylar of New Zealand White rabbits. The animals were divided into three groups: A) treated with the temperature-sensitive hydrogel containing 1-bromoheptafluorooctane with oxygen release; B) treated with the temperature-sensitive hydrogel containing 1-bromoheptafluorooctane without oxygen release; and C) received no treatments. At four and 12 weeks post-operation, the specimens from all groups were collected. The new bone formation was studied by morphological observation, X-ray, Micro-CT, Masson's trichrome, and CD31 immunohistochemical staining. At 12 weeks post-operation, the bone defects were completely healed in groups A and B, while a major bone defect was still present in group C. Micro-CT showed that TMD, BVF, Tb.Th and Tb.N in group A were significantly higher compared to the other groups at each time point post-operation. The SMI value of group A showed a significant difference from the other groups at 12 weeks post-operation. The number of micro-vessels in group A was significantly higher compared to the other groups at four and 12 weeks post-operation. The oxygenating temperature-sensitive hydrogel containing 1-bromoheptafluorooctane could effectively promote new bone formation while increasing tissue vascularization, highlighting a good clinical application prospect. [ABSTRACT FROM AUTHOR]

Background: Frequency of urethral stenosis makes it necessary to develop new innovative methods of treating this disease. This pathology most often occurs in men and manifests itself in painful urination, reduced urine flow, or total urinary retention. This is a condition that requires immediate medical intervention. Methods: Experimental tests were carried out on a rabbit in order to determine the changes of pressure in the urethra system and to estimate the velocity of urine flow. For this purpose, a measuring system was proposed to measure the pressure of a fluid-filled urethra. A fluoroscope was used to observe the deformability of the bladder and urethra canal. Results: Based on these tests, the range of changes in the urethra tube diameter, the pressures inside the system, and the flow velocity during micturition were determined. Conclusions: The presented studies allowed determining the behavior of the urethra under the conditions of urinary filling. The fluid-filled bladder and urethra increased their dimensions significantly. Such large changes require that the stents used for the treatment of urethral stenosis should not have a fixed diameter but should adapt to changing urethral dimensions.

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Introduction: Critical size defects (CSD) in the long bones of New Zealand White rabbits (Oryctolagus cuniculus) have been used for years as an experimental model for investigation of the effectiveness of a new bone substitute material. There are varieties of protocols available in the literature. This technical note attempts to present an alternative surgical technique of a CSD in the New Zealand white rabbit tibia. Methods: Thirty-nine New Zealand White rabbits were used in this study. A CSD of approximately 4.5 mm (width) X 9.0 mm (length) was surgically drilled at the proximal tibial metaphysis, approximately 1 cm from the knee joint. The surrounding of soft tissue was repositioned and sutured layer by layer with bioabsorbable surgical suture. Two x-rays of anteroposterior and lateral were taken before assessed under computed tomography scan at 6, 12 and 24 weeks. Results: This alternative method created CSD with less bleeding from the muscle observed. No mortality or other surgical complications observed within 6 weeks, 12 weeks and 24 weeks following surgery. Conclusion: A simple and safe method for performing CSD was demonstrated and recommended as an alternative approach for surgery on New Zealand White rabbits. [ABSTRACT FROM AUTHOR]