Water-Soluble Chitosan Enhances Bone Fracture Healing in Rabbit Model

Background: Chitin and its derivatives participate and influence many important biological activities, such as antibiosis, modulating immunity, suppressing tumor growth, and promoting wound healing as well as promoting hemostasis. This study aimed at confirming the effects of water-soluble chitosan (ws-chitosan) on accelerating healing of induced fractures in New Zealand white rabbits. Materials and methods: Thirty-six selected New Zealand rabbits (each with a 3mm bone defect in the middle segment of radius) were randomly divided into two groups (control group, n=18 and experimental group, n=18). The two groups of rabbits were given normal saline (1.00mg/kg) and ws-chitosan (0.28g/kg) every day through gastric tubes, respectively. Three postoperative observation time points of 7 days, 14 days and 28 days were selected. X-ray was applied to examine the healing effect; immunohistochemistry was introduced for observing the bone morphogenetic protein-2 (BMP-2) expression, and the fracture healing related biochemical indexes (serum ALP and calcium concentration) were measured and recorded. Results: The X-ray results revealed that the fracture healing effect in experimental group was more remarkable than that in the control group on 7 days, 14 days and 28 days, postoperatively. The BMP-2 expression and the calcium concentration in experimental group on 7 and 14 days were clearly higher than those in the control group, while the serum ALP and calcium concentration in ws-chitosan group were distinctly higher than those in the control group on 7 and 14 days. No adverse events were observed in the study period. Conclusion: Results showed that ws-chitosan can enhance facture healing in rabbit model, for it could not only increase ALP and calcium concentrations in serum, but also promote the osteoblast differentiation and BMP-2 expression for accelerating the healing process. Keywords: Fracture healing, osteoblasts, therapeutic efficacy, water-soluble chitosan.