Effects of highly selective sensory/motor nerve injury on bone metabolism and bone remodeling in rats

OBJECTIVES: This work aimed to investigate the mechanism of selective sensory/motor nerve injury in affecting bone metabolism and remodeling. METHODS: The selective sensory/motor nerve injury rat model was constructed through posterior rhizotomy (PRG), anterior rhizotomy (ARG), or anterior combined with posterior rhizotomy (APRG) at the L(4-6) sensory/motor nerves on the right side of rats. Sham-operated (SOG) rats served as control. At 8 weeks after surgery, the sciatic nerves, spinal cord segments L(5) and tibial tissues were collected for analysis. RESULTS: the integrity of trabecular bone was damaged, the number of trabecular bone was decreased and the number of osteoclasts were increased in ARG group. ARG activated NF-κβ and PPAR-γ pathways, and inhibited Wnt/β-catenin pathway. ARG group exhibited high turnover bone metabolism. In PRG group, the trabecular bone morphology became thinner, and the number of osteoclasts was increased. NF-κβ pathway was activated and OPG/RANKL ratio was decreased in PRG group. The activated osteoclasts, reduced osteoblasts activity and lower turnover bone metabolism were observed in PRG group. Additionally, the bone metabolism in APRG group was similar to ARG group. CONCLUSION: The posterior rhizotomy and anterior rhizotomy induced the different degree of osteoporosis in rats, which may attribute to regulate Wnt/β-catenin, NF-κβ and PPAR-γ signalling pathways.