运动负荷骤降对生长期大鼠长骨骨量和骨代谢生化指标的影响

目的观察运动负荷骤降对生长期大鼠长骨骨量(BMC)、骨密度(BMD)和骨代谢生化指标的影响。方法雄性3月龄SD大鼠48只,随机分成大强度运动组(T1)、大强度转低强度运动组(T2)、低强度运动组(T3)、对照组(Con),每组12只。前6周,T1、T2组进行大强度跑台运动,T3组进行低强度跑台运动。6周末,DEXA测定每组部分大鼠股骨BMC、BMD,酶标仪法测定血清碱性磷酸酶(ALP)、骨钙素(BGP)和抗酒石酸性磷酸酶(TRACP5b)。降低T2组运动负荷,与T3组一致,其余组运动强度不变,继续运动6周。同样方法测定上述指标。结果与运动负荷降低前比较,12周末T2组大鼠ALP、BGP降低(P<0.05),TRACP5b升高(P<0.05),股骨BMC、BMD无显著性差异(P>0.05)。结论运动负荷骤降使成长期大鼠长骨骨形成抑制,骨吸收增强。

Influence of Rapid Reduction of Physical Activity on Bone Mass and Biochemical Markers of Bone Metabolism in Growing Rats

Objective To observe the effect of rapid reduction of physical activity on bone mass(BMC),bone mineral density(BMD) and bone metabolism in growing rats.Methods 48 male SD rats were divided into the high-intensity exercise group(T1,n=12),high to low-intensity exercise group(T2,n=12),low-intensity exercise group(T3,n=12) and control group(Con,n=12).During the first 6 weeks,the rats in T1 and T2 group ran on treadmill with high intensity,while rats in T3 group took low-intensity treadmill exercise.6 rats were sacrificed from each group at the end of 6th week.BMC,BMD of femur were measured with DEXA.Alkaline phosphatase(ALP),osteocalcin(BGP),tartrate-resistant acid phosphatase(TRACP) were detected with ELISA.The exercise intensity of T2 group was reduced rapidly to a low level as in T3 group,but remained in the other 2 groups.At the end of the second 6 weeks,the other rats were investigated again.Results Compared with the first measurements,ALP and BGP of the T2 group decreased significantly(P<0.05),and TRACP increased(P<0.05).There was no significant difference in BMC and BMD of femur(P>0.05).Conclusion Rapid reduction of physical activity can suppress bone formation and stimulate bone resorption of long bone among growing rats.