Abstract:

BACKGROUND: Previous study showed that nervous system plays an important role in the fracture reconstruction. However, the concrete mechanism has not been totally expounded yet. The effect of central nervous and nerve growth factor on callus was rarely reported.
OBJECTIVE: To observe histological changes of callus osteogenesis at tibial fracture site in denervated rats.
METHODS: SD rats were prepared for closed fracture with left tibial intramedullary fixation models and were randomly assigned into 3 groups: Simple left tibial fractures group, T₁₀ spinal cord transaction group: Based on the tibial fracture models, 0.3 cm T^₁₀ spinal cord was transected and removed. Nerve growth factor group: Based on the frontal models, intramuscular injecting nerve growth factor. The morphological changes of bone tissues were observed by hematoxylin-eosin staining. The condition of osteogenesis in callus was observed by osteocalcin immunohistochemistry and the microstructure of osteoblasts was detected under a transmission electron microscope.  
RESULTS AND CONCLUSION: The osteoblasts quantity was decreased, osteocalcin decreased and osteoblasts organelle functions lowered in the T₁₀ spinal cord transaction group. Compared with the T₁₀ spinal cord transaction group, these indexes in the nerve growth factor group were improved. The findings demonstrated that nerve growth factor can partly improve bone tissue regeneration in denervate state.