不同强度运动对去卵巢大鼠骨量的影响及其机理

以成年SD大鼠去卵巢建立骨质疏松模型,用骨形态计量学方法,研究了8周的大强度和中等强度(分别为20m/min和30m/min,1h/day,5d/week)跑台运动对大鼠胫骨近心干骺端松质骨骨量的影响.结果去卵巢安静组大鼠骨量减少(%Tb.Ar-75%,p＜0.01;Tb.N-74%,p＜0.01),骨形成增加(BFB/BS+115%,BFR/BV+123%,P＜0.01)、骨吸收增加(Oc.No+229%,p＜0.01),为高转换型的骨代谢.中等强度运动的去卵巢大鼠比去卵巢安静大鼠骨形成减少(%L.Pm-42%,BFR/BS-36%,P＜0.05),骨吸收减少(Oc.No-42%,p＜0.05),高转换受到抑制,骨量增加(%Tb.Ar+53%,p＜0.05;Tb.N+69%,p＜0.01),但仍比正常组大鼠骨量降低(%Tb.Ar-61%,p＜0.01).去卵巢后大强度运动与去卵巢安静组大鼠各项指标相比无显著性差异(p＞0.05),与中等强度运动比骨形成增加(BFR/BS+121%,P＜0.01),骨吸收增加(Oc.No+103%,p＜0.05),骨量减少(%Tb.Ar-37%,p＜0.05),仍为高转换型骨代谢.结论大鼠去卵巢后中等强度运动通过抑制高骨转换可减少骨丢失,减轻骨质疏松的程度,大强度运动对减轻骨质疏松的程度无作用.

Mechanisms and Effects of Different Intensities Exercise on Bone Mass in Ovariectomized Rats

The effect of different intensities exercise on bone mass of proximal tibial metaphysis was investigated in adult ovariectomized (OVX) rats compared with sedentary OVX and sedentary sham-operated rats(SHAM) by histomorphometric assessment. The exercise rats were trained on a treadmill at 20 m/min (OVX-EX1) or 30 m/min (OVX-EX2) for 1h/day ,5 days/week for 8 weeks.The results showed that in OVX rats, OVX reduced trabecular bone area and number 75% and 74% (P<0.01) respectively,osteoclast number and bone formation rate of bone surface referent were significantly higher 229% and 115% (P<0.01) respectively than in SHAM rats ,indicating increased bone turnover in OVX rats. In OVX-EX1 rats,trabecular bone area and number increased 53% (P<0.05)and 69% (P<0.01),bone formation rate and percent labelled perimeter were lower 36% and 42% (P<0.05) respectively, osteoclast number were lower 42% (P<0.05) than in OVX rats,indicating that moderate exercise suppressed increased bone turnover in OVX rats. High intensity exercise did not affect the histomorphometric parameters significantly compared with OVX rats but decreased trabecular bone area and number 37% (P<0.05) and 45%(P<0.01),also bone formation and resorption parameters higher significantly compared with in OVX-EX1 rats. In conclusion, moderate exercise can reduced the cancellous bone loss on proximal tibial mataphysis in ovariectomized-induced osteoporosis by reduced bone turnover,while high intensity exercise had no significant effect on bone mass.