不同持续时间中等强度运动对去卵巢大鼠骨量及骨微结构的影响

Long-term Moderate Intensity Exercise Inhibits the Bone Loss in Ovariectomized Rats

目的:探讨不同持续时间中等强度跑台运动对去卵巢大鼠骨量及骨微结构的影响。方法:3月龄雌性SD大鼠随机分为9组:去卵巢组(OVX-4、8、12三组),假手术组(SHAM-4、8、12三组),去卵巢+运动组(OVX+T-4、8、12三组),每组10只。运动组采用跑台训练,坡度5°,60分钟/天,5天/周。分别于4、8、12周取材测试。以DXA测定大鼠全身BMD;以骨形态计量学测量大鼠胫骨骨微结构,测试结果主要包括静态参数(BV/TV、Tb.Th、Tb.N和Tb.Sp)和动态参数(Ob.N/mm、%L.Pm、MAR、BFR/BS、Oc.N/mm)两部分。结果:骨密度结果显示,与同期OVX组大鼠相比,OVX+T-4组无显著变化,OVX+T-8、12组显著升高,虽仍低于同期SHAM组,但两者之间无显著性差异。静态参数结果显示,与同期OVX组相比,OVX+T-4组各静态参数均无显著变化;OVX+T-8、12组BV/TV、Tb.Th显著升高,Tb.Sp显著下降,但与同期SHAM组相比仍显著降低。动态参数结果显示,OVX+T-4、8、12组的骨吸收指标(Oc.N/mm)显著低于同期OVX组,骨形成参数无显著性差异;而与同期SHAM组相比,骨吸收参数已无显著性差异,而骨形成参数(Ob.N/mm、%L.Pm、BFR/BS)仍显著升高。结论:持续4周的中等强度跑台运动可抑制去卵巢大鼠骨吸收,但尚未对去卵巢大鼠的密度和骨微结构产生明显影响;持续8周及以上的中等强度跑台运动不仅可以显著抑制去卵巢大鼠的骨吸收,还能够明显改善由于去卵巢所导致的骨密度下降及骨微结构破坏。

Objective We evaluated the effect of moderate intensity treadmill training on the bone mineral density and bone microstructure of ovariectomized rats. Methods We randomly divided 3-month old female Sprague-Dawley rats into SHAM-4 group（4 weeks after pseudooperation）,SHAM-8 group（8 weeks after pseudooperation）,SHAM-12 group（12 weeks after pseudooperation）,OVX-4 group（4 weeks after ovariectomy）,OVX-8 group（8 weeks after ovariectomy）,OVX-12 group（12 weeks after ovariectomy）,OVX＋T-4 group（4-week training after ovariectomy）,OVX＋T-8 group（8-week training after ovariectomy）,OVX＋T-12 group（12-week training after ovariectomy）. Rats in the training groups performed aerobic treadmill training 60 minutes a day,5 days a week at the slope of 5° for 4,8,and 12 weeks,respectively.Histomorphometry was used to observed the proximal tibial microstructure（including BV/TV,Tb.Th,Tb.N,Tb.Sp,Ob.N/mm,% L.Pm,MAR,BFR/BS,and Oc.N/mm）. DXA was applied to evaluate the whole body bone mineral density. Results There was no significant difference in BMD in OVX ＋T-4 group,while significant increase in OVX ＋T-8 and OVX ＋T-12 groups as compared with the respective OVX groups. However,the BMD in all OVX＋T groups was still somewhat lower than the respective SHAM groups. The BV/TV and Tb.Th were significantly higher and Tb.Spin significantly lower in OVX＋T-8 and OVX＋T-12 groups than those in OVX-8 and OVX-12 groups. However,the BV/TV and Tb.Th in all OVX＋T groups were significantly lower the respective SHAM groups. The Oc.N/mm in all OVX ＋T groups was significantly lower than that in respective OVX groups,while insignificant as compared with the respective SHAM groups. The Ob.N/mm,%L.Pm,and BFR/BS in all OVX＋T groups were higher than in respective SHAM groups. Conclusions Four weeks of moderate intensity treadmill exercise inhibited only bone desorption in ovariectomized rats without significant changes in the bone mineral density and microstructure in ovariectomized rats. Eight weeks or longer than eight weeks moderate intensity treadmill training not only inhibited the bone desorption significantly,but also the bone loss,and reduced the microstructural damage of bone in ovariectomized rats.