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Objectives: Tendon recovery after a surgical operation or traumatic injury is still one of the challenges of rehabilitation. Many recently formulated treatments have been designed to improve these procedures. This study aimed to evaluate the effects of recombinant basic fibroblast growth factor (bFGF) and cold atmospheric plasma (CAP) on calcaneus tendon healing and regeneration in rabbit models. Material and Methods: This study subdivided 40 mature male New Zealand white rabbits into four groups (n=10 in each). The defect was made under general conditions, and the wound was closed without treatment. The experimental groups included sham (without treatment), bFGF (operated bFGF in the injured area), CAP (used CAP in the injured area), and bFGF/CAP (used both CAP and bFGF) in the injured area. This study used trichrome and reticulin stains to evaluate collagen production and other tissue factors. Also, hydroxyproline levels were measured for better observation of collagen synthesis. Pathological evaluation of the defective tendon was performed on days 60 and 120 after surgery. Results: The improvement of new and parallel tendon formation was the best in the bFGF/CAP group at both times, especially 120 days after surgery. An increase in hydroxyproline levels was also seen on the sampling days. Conclusions: The experiment showed that bFGF/CAP combination significantly improved tendon remodeling in the injured areas. [ABSTRACT FROM AUTHOR]

BACKGROUND: A large number of studies have confirmed that exosomes can promote osteogenesis and vascularization. However, simple exosome therapy has problems such as poor targeting, and the content of loaded molecules cannot reach the therapeutic concentration. OBJECTIVE: To load exosomes into injectable gluconolactone-sodium alginate β-tricalcium phosphate-polyethylene glycol hydrogel, and observe the effect of the hydrogel on peri-implant bone defect in vivo and in vitro. METHODS: Exosomes were extracted from bone marrow mesenchymal stem cells and wrapped in injectable gluconolactone-sodium alginate β-tricalcium phosphate-polyethylene glycol hydrogel. (1) In vitro experiment: The hydrogel loaded with exosomes and the hydrogel without exosomes were cocultured with endothelial progenitor cells, and exosomes uptake experiment, tubule formation experiment, cell proliferation, migration ability, and angiogenic gene detection were carried out. (2) In vivo experiment: Twelve male New Zealand white rabbits were used to prepare two standard implant cavities and corresponding bone defects in the long axis of one femur. A hydrogel loaded with exosomes was implanted in the bone defect after an implant was implanted in a cavity at the proximal end of the implant (experimental group), and an unloaded exosome hydrogel was implanted in the bone defect after an implant was implanted in a cavity at the distal end of the implant (control group). At 3, 6 and 9 weeks after operation, bone defects with implants were removed and stained with hematoxylin-eosin staining and Masson staining. Simultaneously, osteogenic and angiogenic genes were detected at 9 weeks after operation. RESULTS AND CONCLUSION: (1) In vitro experiment: Exosomes could enter endothelial progenitor cells. The proliferation, migration, angiogenesis and gene (CD31, vascular endothelial growth factor and basic fibroblast growth factor) expression of endothelial progenitor cells in the hydrogel-loaded group were higher than those in the hydrogel-unloaded group (P < 0.05). (2) In vivo experiment: Hematoxylin-eosin staining and Masson staining showed that at 3 weeks after operation, only a small amount of new bone was found in the two groups, and the material was partially degraded. At 6 weeks after operation, the amount of new bone in the two groups increased, and a large amount of new bone was found in the experimental group, with obvious calcium deposition. At 9 weeks after operation, compared with the control group, a large number of bone trabeculae thicker than mature were found in the experimental group, calcium salt deposition was more obvious, and a large number of osteoblasts were found around the bone trabeculae. The protein expressions of CD31, vascular endothelial growth factor, basic fibroblast growth factor, bone morphogenetic protein 2, type I collagen and osteocalcin in the experimental group were higher than those in the control group at 9 weeks after operation (P < 0.05). (3) The exosome-loaded gluconolactone-sodium alginate β-tricalcium phosphate-polyethylene glycol hydrogel could promote the proliferation, migration and angiogenic differentiation of endothelial progenitor cells and promote the repair and regeneration of bone defects around implants. [ABSTRACT FROM AUTHOR]

BACKGROUND: Due to the particularity of the ear structure, the skin at the auricle injury usually has poor motion range and tissue regeneration ability, and it is difficult to heal. Therefore, how to accelerate the wound healing and obtain an ideal repair effect has always been a problem and research hotspot in the field of surgery. OBJECTIVE: To explore the effects of Sanhuang gel on the wound healing, basic fibroblast growth factor and interleukin 17 levels of auricle skin defect in rabbits. METHODS: Sixty male New Zealand rabbits were randomly divided into six groups (n=10 per group). In group A, no treatment was given. In groups B-F, a circular skin defect area with the diameter of 1 cm was made in the auricle. In group B, the wound was injected with physiological saline. In group C, the wound was coated with asiaticoside cream ointment. In group D, the wound was coated with Sanhuang gel. In group E, the wound was injected with PI3K/AKT agonist 740 Y-P. In group F, the wound was coated with Sanhuang gel and injected with 740 Y-P. The treatment was performed twice a day, for 30 consecutive days. The wound healing of rabbit ear was observed and recorded, and the pathological morphology of ear tissue was detected by hematoxylin-eosin staining. The mRNA relative expression levels of basic fibroblast growth factor and interleukin 17 in rabbit ear tissue were detected by real-time PCR. The protein expression of PI3K/AKT pathway in rabbit ear tissue was detected by western blot assay. RESULTS AND CONCLUSION: (1) After treatment, the skin wound healing speed was accelerated. After 30 days of treatment, the wound healing rate of Sanhuang gel and PI3K/AKT agonist alone was higher than that of asiaticoside cream ointment, and the combined application of the two had the highest wound healing rate. (2) Hematoxylin-eosin staining results showed that the epidermis of group B was significantly thickened and blood vessels were dilated; and a large number of infiltrated inflammatory cells and fibrous tissue hyperplasia were seen. Compared with group B, the morphology of groups C, D, E, and F was significantly improved, and new capillaries and numerous proliferated fibroblasts and endothelial cells were seen. Among them, group F had the most obvious improvement. (3) RT-PCR detection showed that the relative expression of basic fibroblast growth factor mRNA decreased and the relative expression of interleukin 17 mRNA increased after auricular skin injury. After different treatments, the relative mRNA expression of the two factors was improved to varying degrees. The improvement effect of Sanhuang gel and PI3K/AKT agonist alone was stronger than that of asiaticoside cream ointment, and the improvement effect of their combination was strongest. (4) Western blot assay showed that the expression of PI3K, AKT, p-PI3K, and p-AKT proteins decreased after auricular skin injury. The expression levels of the four proteins increased to varying degrees after different treatments. The elevating effect of Sanhuang gel and PI3K/ AKT agonist alone was stronger than that of asiaticoside cream ointment, and the elevating effect of their combination was strongest. (5) The results show that Sanhuang gel can promote the wound healing of auricular skin defects, and its mechanism may be associated with the activation of PI3K/AKT pathway. [ABSTRACT FROM AUTHOR]

Purpose: To explore the changes in vitreous body after vitreous hemorrhage and assess its prognosis from the perspective of vitreoretinal interface. Methods: The experiment was performed on 32 New Zealand rabbits (64 eyes), weighing 2500–3000 g for 4 months and unlimited gender, which was injected with 0.2 mL of autologous blood into the center of vitreous cavity–the study group (right eyes), and the control one was treated in the same manner with equal volumes of saline. The rabbits were randomly and equally divided into the following four batches according to the days of observation: Days 3, 7, 14, and 30 after injection. IOP and severity grading were evaluated before rabbits' execution and eyeballs were enucleated. The anterior segment was separated to flow out the vitreous body naturally to detect the liquefaction degree and viscosity. Then, chemical composition of electrolytes, PCT and bFGF were determined by colorimetry and enzyme-linked immunosorbent assay (ELISA). Finally, the incidence of posterior vitreous detachment (PVD) was observed after vitreous sampled. The studies were double-blind. Results: After injection, the extent of vitreous opacity and coagulum size decreased over time. Both the degree of liquefaction and the length of tow differed significantly between two groups at different time points (all p < 0.001). The liquefaction degree in the study group rose obviously from the Day 14, which the viscosity declined significantly on the initial time. Biochemical markers fluctuated temporarily, except for basic fibroblast growth factor (bFGF), which continued to rise and was correlated with the liquefaction degree (r = 0.658, p < 0.001). Besides, the incidence of PVD increased from the 14th day (p < 0.05), and it was highly positively correlated with the number of macrophages (r = 0.934; p < 0.001). Conclusion: After vitreous hemorrhage, the changes of the vitreous body are relatively minor earlier (2–4 weeks), but irreversible later. Specifically, the degree of liquefaction increases with a decrease in viscosity, and the chemotaxis of macrophages and bFGF induce incomplete PVD. [ABSTRACT FROM AUTHOR]

BACKGROUND: As one of the effective angiogenic factors, basic fibroblast growth factor can not only increase the blood perfusion of ischemic tissues and accelerate the regeneration of tissue microvessels, but also improve the formation of blood vessels in muscle tissues and increase the blood perfusion of muscles. OBJECTIVE: Basic fibroblast growth factor was incorporated into poly(lactic acid)/collagen scaffold to repair rabbit urethral defects and to improve the ability of tissue engineered scaffolds to induce urethral regeneration. METHODS: The electrospun poly(lactic acid)/collagen urethral scaffold and the electrospun poly(lactic acid)/collagen scaffold loaded with basic fibroblast growth factor were prepared and named as control scaffold and experimental scaffold, respectively. The in vitro release properties of the scaffolds were tested. The third passage of rabbit adipose derived mesenchymal stem cells was seeded on the two scaffolds for 7 days. CCK-8 assay, cell adhesion test, and cell livedead staining were performed respectively. Twenty-four adult male New Zealand white rabbits were used to establish a 5 cm long urethral defect model and randomly divided into two groups (n=12). The control scaffold + adipose derived mesenchymal stem cell complex and the experimental scaffold + adipose derived mesenchymal stem cell complex were implanted, respectively. At 12 and 24 weeks after operation, retrograde urethrography and histology were performed. RESULTS AND CONCLUSION: (1) In vitro sustained release experiment: Basic fibroblast growth factor was released at an average rate of 2.5 ng/d in the first 6 days, 1.52 ng/d from the seventh to fourteenth days, and 1.12 ng/d thereafter. The release rate gradually decreased after 21 days. (2) In vitro cell experiments showed that the cell proliferation rate on the experimental scaffold was faster than that on the control scaffold (P < 0.05). Adipose-derived mesenchymal stem cells could adhere to the surfaces of the two scaffolds, grow well and protrude pseudopodia, among which the cells on the experimental scaffold proliferated rapidly. The survival rate of the cells on the experimental scaffolds was higher than that of the control scaffold (P < 0.05). (3) In vivo experimental results: At 24 weeks postoperatively, urethral angiography exhibited that there was no urethral stricture in the experimental scaffold group, and mild urethral stricture was seen in the control scaffold group. Histological observation demonstrated that at 24 weeks after operation, there was a thick and complete epithelial layer in the experimental scaffold group, with a large number of muscle fiber bundles and blood vessels. In the control scaffold group, there was a thin epithelial layer, with a small number of muscle fiber bundles and blood vessels. (4) The results confirm that electrospun poly(lactic acid)/collagen scaffold loaded with basic fibroblast growth factor for repairing rabbit urethral defects could promote local angiogenesis, improve local urethral microenvironment and promote urethral regeneration. [ABSTRACT FROM AUTHOR]

Open in new tab Download slide Open in new tab Download slide OBJECTIVES For the technical management of tracheal anastomosis, developing new and simple methods is required to relieve anastomotic tension. This study aimed to investigate whether basic fibroblast growth factor (bFGF) only once injected immediately before anastomosis promotes cartilage regeneration at the tracheal anastomosis and whether the regenerated cartilage has the effect of reinforcing the anastomosis in a rabbit model. METHODS New Zealand white rabbits were anaesthetized, and the cervical trachea was exposed through a cervical midline incision, followed by resection of the 10th tracheal cartilage. The rabbits were categorized into 2 groups: the bFGF group (n  = 6) and the control group (n  = 6). In the former group, bFGF (25 μg) was administered into the submucosal layer of the cartilage using a 27-G needle immediately before tracheal anastomosis. The animals were sacrificed 4 weeks later. Histological, mechanical and biochemical evaluations were performed on this anastomosed trachea. RESULTS At 4 weeks of age, the anastomoses were spindle-shaped and displayed maximum diameter at the injection site compared with those in the control group. Histological evaluation showed that cartilage tissue had regenerated between the 9th and 11th tracheal cartilage rings. Tensile test showed that the anastomoses displayed a significantly high strain/stress ratio (P   =  0.035). The collagen type II and glycosaminoglycan levels were significantly increased, and the collagen type I level was significantly decreased (P  = 0.019, P  = 0.013 and P  = 0.045, respectively). CONCLUSIONS A new wound-healing concept of airway anastomosis could be provided by the results that single injection of bFGF regenerated tracheal cartilage in rabbits and strengthened the anastomosis by bridging the regenerated and well-matured cartilage. Further investigation of this method will lead to potential clinical applications for reinforcement of tracheal anastomoses. [ABSTRACT FROM AUTHOR]

BACKGROUND: Some studies have shown that basic fibroblast growth factor can promote the proliferation and osteogenic differentiation of mesenchymal stem cells. OBJECTIVE: To compare the ability of acellular bone matrix/chitosan scaffold combined with basic fibroblast growth factor in repairing rabbit femoral defect. METHODS: The acellular bone matrix/chitosan scaffolds were prepared by fusion blending and freeze-drying method, and the acellular bone matrix/chitosan scaffold loaded with basic fibroblast growth factor was prepared by immersion method. Mouse embryonic osteoblasts MC3T3-E1 were seeded on the surface of the two scaffolds for cell proliferation, cell adhesion and osteogenic gene detection. Cells cultured alone served as control. Bone defect models with a diameter of 5 mm were made in bilateral distal femurs using thirty-six 6-month-old New Zealand white rabbits and randomly divided into three groups by drawing lots. The blank group was not intervened. The simple composite scaffold and growth factor + composite scaffold groups were implanted with acellular bone matrix/chitosan scaffold and acellular bone matrix/chitosan scaffold loaded with basic fibroblast growth factor for X-ray and histological examination. RESULTS AND CONCLUSION: (1) Within 1-11 days of culture, the cell proliferation of basic fibroblast growth factor/acellular bone matrix/chitosan scaffold group was faster than that of the acellular bone matrix/chitosan scaffold group (P < 0.05), and that of the acellular bone matrix/chitosan scaffold group was faster than that of the control group (P < 0.05). (2) After 4 days of co-culture with the scaffold, the mRNA expressions of type I collagen, osteocalcin, osteopontin and Runx2 were higher in the cells in basic fibroblast growth factor/acellular bone matrix/chitosan scaffold group cultured for 4 and 7 days than those of acellular bone matrix/chitosan scaffold group (P < 0.05), and the mRNA expression of alkaline phosphatase was higher than that of acellular bone matrix/chitosan scaffold group after 7 days of culture (P < 0.05). (3) Scanning electron microscopy showed that the scaffolds of the two groups supported the adhesion of MC3T3-E1 cells after 7 days of co-culture. (4) X-ray film of animal experiment showed that there was no obvious bone repair in the blank group at 12 weeks after operation; new bone formation could be seen at 8 weeks after operation in the simple composite scaffold group, and obvious new bone formation could be seen at 12 weeks after operation; new bone formation could be seen at 4 weeks after operation in the cytokine + composite scaffold group, and the bone defect site was almost completely repaired at 12 weeks after operation (5) Hematoxylin staining and Masson staining showed that a large amount of fibrous tissue could be seen in the blank group at 12 weeks after operation; a large amount of new bone formation could be seen in the two scaffold groups, in which the area and maturity of new bone formation in the growth factor + composite scaffold group were higher than those in the simple composite scaffold group. (6) The results showed that the acellular bone matrix/chitosan composite scaffold loaded with basic fibroblast growth factor is an ideal bone tissue repair material, which can promote bone formation. [ABSTRACT FROM AUTHOR]

BACKGROUND: In recent years, resveratrol has been studied a lot on the inhibition of tissue fibrosis, but the effect of resveratrol on the rehabilitation of muscle injury has been rarely reported. OBJECTIVE: To observe the expression of basic fibroblast growth factor (bFGF) and insulin-like growth factor 1 (IGF-1) protein in the repair of acute blunt trauma of the skeletal muscle, and to explore the mechanism by which resveratrol promotes the structural and functional recovery of damaged skeletal muscle. METHODS: Thirty-three New Zealand rabbits were randomly divided into three groups: normal group (n=3), natural recovery group (n=15) and resveratrol group (n=15). The skeletal muscle contusion model was established by blunt violence except for the normal group. The natural recovery group was not treated and the resveratrol group was intragastrically given resveratrol after injury. The animals were euthanized at 1, 3, 7, 14, and 21 days after injury. Infiltration of inflammatory cells and formation of collagen fibers were observed using hematoxylin-eosin staining and Masson staining. The expression of bFGF and IGF-1 protein in the skeletal musde was detected by immunohistochemistry and immunoblotting. RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining results: In the nonnal group, the muscle fibers were presented with polygons, regular shape, tight arrangement, muscle nucleus evenly distributed under the sarcolemma, no hyperplasia and pyknosis, and sarcolemma intact. In the injury groups, blood cells were exuded at 1 day, and inflammatory cells infiltrated at 3 days, which reached the maximum at 7 days. The morphology of muscle fibers returned to normal at 21 days after injury. The resveratrol group was better than the natural recovery group in terms of inflammatory cell infiltration and repair time. (2) Masson staining results: There were few collagen fibers in normal muscle cells. After injury, the number of collagen fibers increased with the formation of scar tissue, and reached a peak at 14 days. The content of collagen fibers in the resveratrol group was lower than that in the natural recovery group. (3) lmmunohistochemistry and immunoblotting results: The expression of bFGF and IGF-1 protein first increased and then decreased after injury. In both groups, the expression of bFGF and IGF-1 protein reached the peak at 7 days and was still at a high level at 21 days. The resveratrol group had significantly higher bFGF and IGF-1 levels than the natural recovery group (P < 0.05). Overall, resveratrol can effectively accelerate the histological healing process and improve the healing quality of rabbit skeletal muscle after blunt trauma. Resveratrol significantly promotes the repair of damaged skeletal muscle by up-regulating bFGF and IGF-1 expression, but not altering the overall change of protein expression during skeletal muscle injury repair. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to evaluate the effect of Hypericum perforatum (HP) oil on wound-healing process in rabbit palatal mucosa. Materials and Methods: Thirty-six New Zealand albino rabbits were randomly allocated to following groups; (1) HP oil (test, n = 18) and (2) olive oil (control, n = 18). Palatinal excisional wounds were created and the oils were topically applied (0.1 ml, 30 s, twice a day). Gingival biopsies were excised, and analyzed for re-epithelialization (RE) and granulation tissue maturation (GTM) on days 3, 7, and 14 after surgery. Levels of vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF-2) were assessed using the immunohistochemical method. Apoptotic cells (ACs) were evaluated using TUNEL staining. Enzyme-linked immunosorbent assay was used to assess tissue catalase (CAT) and malondialdehyde (MDA) levels. Results: RE and GTM were completed earlier in the HP oil group than in the control group. The number of positively stained cells/vessels was higher in olive oil than in the test group on day 3 for FGF-2 and on days 3 and 7 for VEGF (p < 0.05). In contrast, on day 14, a higher number of vessels was observed in the HP oil group than in the control group. HP oil treatment reduced the number of ACs compared to olive oil (p < 0.05), but the difference during the healing period did not reach significance. Tissue CAT and MDA levels between groups were not different, and also the results were the same when the levels were analyzed by the evaluated time periods (p > 0.05). Conclusions: The results of this study demonstrated that topical HP oil treatment did not provide an additional benefit to its base, olive oil, in the early phase of secondary wound healing. [ABSTRACT FROM AUTHOR]

Statins may precipitate the onset of type 2 diabetes (T2D) in high-risk patients. In contrast, only the subset of individuals with insulin resistance and/or diabetes receives cardiovascular benefits with fibrates. In this context, previous observations from our laboratory suggested that atorvastatin induced an increase in visceral adipose tissue (VAT), whereas fenofibrate had the opposite effects in rabbits. Therefore, we determined the mass, morphology, and vascularization of VAT in New Zealand white rabbits (n = 6/group) that received 0.33 or 2.6 mg/kg/d of atorvastatin or fenofibrate, respectively, during 2 months. As expected, the cholesterol from the atorvastatin group was lower after treatment, while triglycerides decreased in the fenofibrate group. The mass of VAT from the fenofibrate group was 46% lower compared to the controls, meanwhile atorvastatin was associated with a larger diameter of adipocytes (+65%) than that of the control and fenofibrate groups. Fibroblast growth factor 2 (FGF2) gene expression was lower in the fenofibrate group than in the control group (-54%). By contrast, vascular endothelial growth factor A (VEGF-A) gene expression in fenofibrate-treated rabbits was 110% higher than in the control group. In agreement with the gene expression, the marker of angiogenesis platelet endothelial cell adhesion molecule 1 was slightly but significantly higher (+10%) in rabbits treated with fenofibrate than in controls, as determined by immunohistochemistry. These results suggest that fenofibrate is associated with a favorable remodeling of VAT, that is, reduced mass and increased vascularization in normolipemic rabbits; in contrast, atorvastatin induced a nonfavorable remodeling of VAT. These results may be related to the cardiovascular benefits of fenofibrate and the increased risk of T2D in high-risk patients induced by atorvastatin. [ABSTRACT FROM AUTHOR]

Background Platelet concentrates have been used in tissue regeneration. The purpose of this study was to examine effects of growth factors released from leukocyte- and platelet-rich fibrin (L-PRF) and concentrated growth factor (CGF) on the osteogenic differentiation of periodontal ligament fibroblasts (PDLFs). Methods Leukocyte- and platelet-rich fibrins, CGFs and PDLFs were obtained from New Zealand rabbits. The release of basic fibroblast growth factor (bFGF), bone morphogenetic protein 2 (BMP-2) and transforming growth factor β1 (TGF-β1) from L-PRFs and CGFs was measured at 5 h and 1, 3, 5, 7 days, using the enzyme linked immunosorbent assay. The PDLFs were treated with exudates of L-PRF or CGF. After the treatment, cell counting kit-8 assay was performed at day 1, 3, 5 and 7. Alkaline phosphatase (ALP) assay and Western blotting were applied at day 7. Three blocking antibodies were used to neutralize the proteins of bFGF, BMP-2 and TGF-β1. Results Leukocyte- and platelet-rich fibrin and CGF showed different growth factor release pattern, but similar accumulated concentration of these growth factors. PDLFs proliferation was significantly promoted by both L-PRF and CGF at day 1, 3 and 7, and CGF group was superior to L-PRF group at day 1 and 3. Both L-PRF and CGF significantly enhanced PDLFs ALP activity and protein expression of osteogenic markers. The osteopontin level was higher in CGF group than in L-PRF group, but no significant differences were found between two groups for ALP activity. Three blocking antibodies significantly downregulated both L-PRF and CGF induced osteogenic markers expression. Conclusion Both CGF and L-PRF can promote the proliferation and osteogenic differentiation of PDLFs. The bFGF, BMP-2 and TGF-β1 are involved in both L-PRF and CGF induced osteogenic differentiation of PDLFs. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract With increasing demand for treatment of glottal insufficiency, several injection materials have been examined. However, biological resorption, degradation of injected materials, and the subsequent need to perform multiple injections still remain major clinical problems. In this study, we fabricated two different growth factor (GF) [single basic fibroblast growth factor (bFGF), single hepatocyte growth factor (HGF), or dual bFGF/HGF]-immobilized polycaprolactone (PCL)/Pluronic F127 microspheres. These materials were investigated for their potential use as bioactive injection laryngoplasty agents. HGF was found to be continuously released over 20 days and the bFGF was found to be continuously released over 25 days, as demonstrated by ELISA assay. Human vocal fold fibroblasts (hVFFs) showed significantly higher proliferative ability on dual GF-immobilized microspheres. GF-immobilized microspheres (bFGF, HGF, and dual GF) were injected into paralyzed vocal folds of New Zealand white rabbits. Through endoscopic observation and H&E staining, we identified that the microspheres remained localized at the injection site, resulting in constant volume augmentation of the paralyzed vocal fold without significant loss of the initial volume after 4 weeks. The expression of genes related to the extracellular matrix (ECM) in the vocal fold was upregulated by dual GF-immobilized microspheres. Furthermore, dual GF-immobilized microspheres inhibited muscle degeneration and upregulation of myogenic-related genes. In conclusion, dual GF-immobilized microspheres passively augmented the volume of the paralyzed vocal fold while actively inducing ECM synthesis at the injected vocal fold and preserving muscle tissue. Dual GF-immobilized microspheres could be a new and promising injection material for paralyzed vocal folds. Statement of Significance Limitation of prolonged augmentation of vocal fold and degeneration of vocal fold tissue still remain as major clinical problems in the treatment of vocal fold paralysis. Herein, we fabricated the polycaprolactone (PCL)/Pluronic F127 microspheres to augment volume of paralyzed vocal folds. On top of that, we additionally immobilized the growth factors (bFGF, HGF, or dual bFGF/HGF) on the surface of these microspheres. We highlight the efficacy of the dual GF-immobilized microspheres which augmented the volume of the paralyzed vocal fold passively, induced ECM synthesis actively at the injected vocal fold and preserved laryngeal muscle tissue. Our results suggest that the dual GF-immobilized microsphere could be a new promising injection material for injection laryngoplasty to treat paralyzed vocal fold. [ABSTRACT FROM AUTHOR]

Wound healing is a process regulated by a complex interaction of multiple growth factors including fibroblast growth factor 2 (FGF2). Although FGF2 appears in several tissue engineered studies, its applications are limited due to its low stability both in vitro and in vivo. Here, this shortcoming is overcome by a unique nine-point mutant of the low molecular weight isoform FGF2 retaining full biological activity even after twenty days at 37 °C. Crosslinked freeze-dried 3D porous collagen/chitosan scaffolds enriched with this hyper stable recombinant human protein named FGF2-STAB® were tested for in vitro biocompatibility and cytotoxicity using murine 3T3-A31 fibroblasts, for angiogenic potential using an ex ovo chick chorioallantoic membrane assay and for wound healing in vivo with 3-month old white New Zealand rabbits. Metabolic activity assays indicated the positive effect of FGF2-STAB® already at very low concentrations (0.01 µg/mL). The angiogenic properties examined ex ovo showed enhanced vascularization of the tested scaffolds. Histological evaluation and gene expression analysis by RT-qPCR proved newly formed granulation tissue at the place of a previous skin defect without significant inflammation infiltration in vivo. This work highlights the safety and biocompatibility of newly developed crosslinked collagen/chitosan scaffolds involving FGF2-STAB® protein. Moreover, these sponges could be used as scaffolds for growing cells for dermis replacement, where neovascularization is a crucial parameter for successful skin regeneration. [ABSTRACT FROM AUTHOR]