周围神经系统对骨折愈合影响的实验研究

Effects of peripheral nervous system on fracture healing

目的研究周围神经系统在骨折愈合早、中期所起的作用。方法将大鼠一侧下肢制成失神经胫骨骨折模型,对侧制成正常神经支配骨折模型。骨折后15d、30d处死大鼠,取双侧胫骨,拍X线片、测定生物力学强度,制备不脱钙切片,进行骨计量学观察。结果X线片显示失神经组骨痂形成量明显增多(P<0.01),但抗弯强度降低(P<0.05)。骨计量学显示,失神经组矿化骨小梁宽度明显减小(P<0.05),类骨质宽度增加,破骨细胞指数及骨吸收表面明显增大(P<0.05),成骨细胞指数及骨形成表面两组无差别。动态参数显示失神经组矿化沉积率明显变小(P<0.05),类骨质成熟时间延长(P<0.05)。结论周围神经在骨折愈合早、中期起重要的调节作用,完整神经支配是骨折愈合所必需的。

Objective To study the effects of peripheral nervous system on early and middle periods of fracture healing. Methods Denervated tibia fracture model and innervated tibia fracture model were made at the same rat. The animals were executed at day 15 and day 30 after operation respectively. Callus sizes were evaluated by radiograph. The mechanical properties of calluses were recorded in a three point bending test. The callus microstructures were measured by bone histomorphometry.Results Radiograph showed an increased callus formation in the denervated group both on day 15 and day 30 after operation (P< 0.05), but the denervated sides were mechanically weaker. Both on day 15 and day 30, bone histomorphometry showed that mineralized trabecular width significantly decreased and osteoid width increased on the denervated sides as compared with the normally innervated sides (P< 0.05). The parameters of bone resorption, such as osteoclast index and trabecular osteoclastic resorption surface on denervated sides, significantly increased compared with those of the control sides (P< 0.05) whereas osteoblast index and osteoblast bone formation surface had no significant difference (P >0.05). Compared with the innervated groups, 30 days dynamic parameters indicated that mineral appositional rates of the denervated sides significantly decreased (P< 0.05) and that bone mineralization was obviously inhibited. Conclusion Peripheral nervous system may play an important role during earlier and middle periods of fracture healing. Intact innervation is essential for normal fracture healing.