The Changing Features Of The Opg-rankl-rank Expressing On The Progressive Increase Of Training Load Of Female Rats

Objectives:Model of bone induced by training was established though 17 weeks' training under progressive increasing load to the Sprague-Dawley rats.We observed the characteristic of the changes of the OPG and RANKL(OPG-RANKL-RANK signal pathway),and further explored the mechanisim of the bone loss in over-training female rats.Methods:225 three-month old SD female rats were divided into training group (n=120), control group(n=105) randomly. Treadmill training load and of training group refered to the Bedford exercise standard and Pro.Zhemg Lu pre-established animal model of disordered estroud cyclel. The samples were takens at 4w,9w,13w,15w and 17w respectively. Bone mineral density (BMD) was tested, take the right femur demineralized, and OPG and RANKL protein expression of right femur were measured by immunohistochemistry. All data used SPSS13.0 for statistical analysis analysis.Result: Training group rats BMD had been increased progressively during 13w training, and it decreased at 13w. BMD at 15,17w were lower than the control group significantly (p<0.01). E2 of the training group at 9w and 17w over the same period, lower than the control group has a very significant difference. E2 in 13w is lower than control group, significant difference (P<0.05).OPG protein expression of training group inceased at 4w and 9w, started to descend after 13w,and became weaker at 15w,17w. RANKL protein expression of training group was the weakest at 4w, and became stronger at 15w, 17w gradually.Conclusions:Model of bone loss induced by training was established successively though 17weeks'progressive increasing load training. Appropriate training resulted in higher OPG expression and lower RANKL expression. Bone formation was predominant compared with bone absoption. Whereas the long-term over load training led to lower OPG expression and higher RANKL expression, bone absorption was prior to bone formation.