不同强度运动和雌激素联合作用对去卵巢大鼠骨骼生物力学性能的影响

目的:探讨不同强度运动和雌激素联合作用对去卵巢大鼠骨骼生物力学性能的影响。方法:将80只成年雌性SD大鼠按体重随机分为基础对照组、假手术组、骨质疏松对照组、雌激素对照组、低强度运动组、低强度运动加雌激素组、中等强度运动组、中等强度运动加雌激素组、大强度运动组以及大强度运动加雌激素组,利用858BIONIX生物力学检测系统测定8周实验后各组大鼠股骨颈最大载荷、第2腰椎最大凹入载荷和第3腰椎最大压缩载荷。结果:(1)与假手术组比,骨质疏松对照组的股骨颈最大载荷、第2腰椎最大凹入载荷和第3腰椎最大压缩载荷3项力学性能指标分别降低了50%、40%和27%(P<0·05)。(2)与骨质疏松对照组和雌激素对照组比,大鼠去卵巢后3种强度的单纯运动组和运动加雌激素联合组股骨颈最大载荷均显著增加(P<0·05),且随运动强度的增加而增加(P<0·05);相同强度下,运动加雌激素联合组的股骨颈最大载荷与单纯运动组无显著性差异。(3)单纯大强度运动组的第2腰椎最大凹入载荷和第3腰椎最大压缩载荷较骨质疏松对照组和雌激素对照组显著增加(P<0·05);低强度运动加雌激素组第2腰椎最大凹入载荷和第3腰椎最大压缩载荷两项力学指标既显著高于单纯低强度运动组(P<0·05),也显著高于雌激素对照组(P<0·05)。中等强度运动加雌激素组的第2腰椎最大凹入载荷显著高于单纯中等强度运动组(P<0·05)及雌激素对照组(P<0·05)。结论:单纯运动对力直接作用部位的力学性能———股骨颈最大载荷的影响大于单纯补充雌激素,运动和雌激素无明显协同作用;对于非力直接作用部位的力学性能———第2腰椎最大凹入载荷及第3腰椎最大压缩载荷,运动和雌激素联合有一定的协同作用。

Effects of Combination of Exercise with Different Intensities and Administration of Estrogen on Bone Biomechanical Property in Ovariectomized Rats

Objective Effects of combination of exercise with different intensities and administration of estrogen on bone biomechanical property in ovariectomized rats were evaluated. Methods Eighty female SD rats,3 months of age, were either sham-operated (SHAM) or ovariectomized(OVX) and assigned as follows: BASAL (baseline group), SHAM(sham-operated), OVX,OVX+ES (ovariectomy with estrogen administration), OVX+EX1, OVX+EX2, OVX+EX3, OVX+EX1+ES, OVX+EX2+ES, and OVX+EX3+ES. The biomechanical property measurements of maximal load of femoral neck(FN), maximal indentation load of L2 and maximal compression load of L3 in rats were performed using biomechanical property machine, MTS MINI 858 BIONIX(USA). Results (1)Three mechanical indices of FN,L2 and L3 in rats of OVX decreased by 50% (P<0.05),40%(P<0.05) and 27%(P<0.05), respectively as compared with that of SHAM. (2)Ovariectomized rats with exercises alone or combined estrogen administration and exercises exhibited significantly(P<0.05) greater levels of maximal load of FN than rats of OVX and OVX+ES, and this responses had a positive liner correlation (P<0.05)with exercise intensities in rats with exercises alone. In the two groups of the same exercise intensity, no better collaborate effects were observed with exercise and estrogen. (3)Only the exercise with heavy intensity alone induced the significant increase(P<0.05) in this two mechanical parameters comparing with the groups of OVX and OVX+ES. In two groups of the same intensity exercise, both of the two mechanical data were higher in OVX+EX1+ES,not only than that in OVX+ES, but also than that in OVX+EX1, revealing that there is a collaborate effect of estrogen and exercise. There was a same result with the maximal indentation load in OVX+EX2+ES. Conclusions The exercise more profoundly affects the mechanical properties in femoral neck loaded directly than estrogen does and there was no collaborate effect of exercise and estrogen in this part of bone. The effects of estrogen on lumbar vertebral body loaded indirectly are better than that in femoral neck and there are collaborate effects of estrogen and exercise.