Neurotrophin-3 improves fracture healing in rats.

OBJECTIVE: This study aimed at investigating the role of Neurotrophin-3 (NT-3) in the bone fracture healing of rats and to provide a reference for clinical treatment.

MATERIALS AND METHODS: 40 Sprague-Dawley (SD) rats were randomly divided into control group and NT-3 group. The tibia fracture model was made in NT-3 group, and the tibia bone mineral density (BMD) was measured before and after the surgery. The biomechanics indexes were inspected after the surgery, including elasticity modulus, max load, and bending rigidity. The levels of bone morphogenetic protein (BMP)-2 and transforming growth factor (TGF)-β1 in serum were examined by enzyme-linked immunosorbent assay (ELISA). Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the levels of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) mRNA expression in callus tissue. The pathological profile of tibia fracture healing was characterized after the surgery.

RESULTS: The levels of BMD in NT-3 group were significantly higher than that in control group after the surgery (p < 0.05). The levels of elasticity modulus, maximum load, stiffness of shinbone, BMP-2 and TGF-β1 were significantly higher in NT-3 group than those in control group after the surgery (p < 0.05). Compared with the control group, the expression of HIF-1α mRNA was significantly lower and the expression of VEGF mRNA was significantly higher in NT-3 group after the surgery (p < 0.05). Histological study showed that the periosteal reaction, capillary proliferation, cartilage cells production and ossification were happened after treating NT-3 for tibia fracture model rats.

CONCLUSIONS: NT-3 can significantly improve fracture healing in rats.