ABSTRACT
BACKGROUND: The nervous system has been proved to play an important role in fracture healing, and different nervous components exert different effects on bony callus.OBJECTIVE: To observe the callus volume and morphological changes in the fracture healing progress of the rats with spinal cord hemisection and fracture.METHODS: Forty-eight male Sprague-Dawley rats were divided into two groups, and the models of simple fracture and spinal cord hemisection by cutting the right spinal cord combined with fracture were established. The tibia was removed at 14 and 28 days after surgery, and the wet weight was measured, the fracture healing was observed by X-ray examination, morphological changes of the callus were observed through hematoxylin-eosin staining, and the expression level of calcitonin gene-related peptide mRNA in the broken bones was detected by SYBR Green qPCR.RESULTS AND CONCLUSION: In the combination group, the wet weight of the contralateral tibia was more than that of the affected side (P < 0.05), which both were more than those in the simple group (P < 0.05). X-ray findings showed that the combination group had the largest lateral callus, followed by the affected side, and the smallest in the simple group.Hematoxylin-eosin staining showed that in the combination group, the contralateral cells arranged in disorder, while the fibrous callus and cells in regular arrangement were found in the affected side; there were bony callus and cells in regular arrangement in the simple group at 28 days after surgery. SYBR Green qPCR results revealed that the expression level of calcitonin gene-related peptide mRNA in the simple group was significantly higher than that in the combination group (P < 0.05). To conclude, complete innervation is a necessary factor for fracture healing.