脉冲电磁场及阿仑膦酸钠对脊髓损伤大鼠骨质量的影响

目的探讨早期应用脉冲电磁场（PEMFs）和／或阿仑膦酸钠（ALN）对脊髓损伤（SCI）后大鼠骨质量的影响。方法将62只3月龄雌性sD大鼠随机分为5组，其中假手术组仅行椎板切除术，SCI组、SCI＋ALN组、SCI＋PEMFs组及SCI＋PEMFs＋ALN组行脊髓完全横断术，后3组于术后1周时分别给予ALN和／或PEMFs治疗；于术后8周时取材，检测各组大鼠股骨骨密度值、生物力学指标以及胫骨近端骨组织形态计量学等指标。实验所得数据比较采用单因素方差分析及析因分析。结果早期应用ALN和／或PEMFs均可使股骨骨密度、股骨弹性载荷、最大载荷等生物力学指标增高，胫骨近端骨小梁面积百分比也同时增大，骨小梁宽度增加。结论早期应用ALN和／或PEMFs均可抑制SCI后骨量丢失，增强抗骨折能力，阻止胫骨近端微观结构的退变，提示早期应用ALN及PEMFs有助于防治SCI后骨质疏松，但其具体治疗机制还有待进一步研究。

Effect of early intervention on bone mass and biomechanical properties of femur in rats after spinal cord injury

Objective To explore the effect of early administration of alendronate (ALN) and pulsed electromagnetic fields (PEMFs) on bone mass of rats after spinal cord injury(SCI). Methods Sixty-two healthy female SD rats aged 3 months were randomly allocated into 5 groups: a Sham group, a SCI group, a SCI+ALN group, a SCI+PEMFs group and a SCI+PEMFs+ALN group. Rats in the Sham group underwent laminectomy, while the rats in the other 4 groups underwent complete spinal cord transection, and the remained 3 groups were treated with ALN and/or PEMFs 1 week after SCI. All rats were sacrificed 8 weeks after operation. The bone mineral density(BMD), biomechanical parameters of the femurs, and histomorphometric parameters of proximal tibias were mea-sured, respectively. The data were analyzed with one way-ANOVA and factorial design-ANOVA. Results After early treatment of ALN and/or PEMFs, the BMD of femur was significantly increased as compared with that of rats in the SCI group; the elastic load, maximal load of femur were significantly increased as compared with those of rats in the SCI group; the percent trabecular bone area and trabecular bone width of tibias were significantly increased when compared to those of rats in the SCI group. Conclusion Early treatments of ALN and PEMFs can reduce the loss of bone, improve biomechanical properties of the femur, and inhibit the decay of microstructure of upper part of tibia. The study suggests that ALN and PEMFs may help prevent osteoporosis after SCI.