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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]

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]

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]

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Objective: To establish and evaluate chronic stress model in New Zealand white rabbit with hyperlipidemia. Methods: A total of 45 clearing grade male New Zealand white rabbits were divided into four groups with random number table method: control (CON), normal diet combined with chronic stress for 8 weeks (CON+ CS), high fat diet (HFD) and high fat diet for 4 weeks combined with chronic stress for 8 weeks (HFD+ CS). Both social stress and physical stress methods were adopted.One-way ANOVA was used for comparison among groups. Results: (1) Chronic stress model assessments: ①body weight, the weight gain of stress groups was significantly reduced; ②behavioral assessment, rabbits exposed to stress in CON+ CS and HFD+ CS group [54%±7%, 55%±5%] exhibited more inactivity behavior than CON and HFD group [27%±5.28%, 34%±6%, P <0.01, P <0.05]; ③serum indexes: after stress regime for 4 weeks, cortisol of HFD+ CS was higher than HFD group [(60±5) ng/ml vs (38±4) ng/ml, P =0.001]. After 8 weeks, the serum levels of hs-CRP and IL-6 also elevated. (2) The effect of hyperlipidemia on chronic stress: compared with CON+ CS, HFD+ CS group showed more inactivity behavior and rising levels of cortisol, hs-CRP and IL-6. (3) Blood lipids: chronic stress induced raised serum total cholesterol. Conclusions: (1)Chronic stress model in rabbit with hyperlipidemia could be successfully established with 4-week high lipid feed followed by social stress combined with physical stress for 8 weeks.(2) Hyperlipidemia and chronic stress influences each other.