Effects of activity restriction on the physical characteristics,biomechanical properties and bone morphogenetic protein 2 expression of femur and tibia in rats

AIM:To investigate the effects of activity restriction on the physical characteristics,biomechanical properties and bone morphogenetic protein 2(BMP2)expression of femur and tibia in rats.METHODS:Totally 32 male SD rats were randomly divided into experimental group and control group.In the experimental group 16 rats' posterior limbs were fixed together with tails to restrain their activity for 4 weeks.Thereafter the 32 rats were executed to weigh the wet weight,gray weight,and detect the bone mineral content(BMC),bone mineral density(BMD)by dual energy X-ray absorptiometry(DPX)and some important biomechanical parameters of femur and tibia and BMP2 expression by immunohistochemistry in experimental group and control group.RESULTS:The wet weight,gray weight,BMC and BMD of femur and tibia were all reduced significantly in the experimental group and expression of BMP2 was also decreased markedly in experimental group as compared with control group.CONCLUSION:Activity restriction has negative effects on bone morphogenesis of posterior limbs and BMP2 may be an important factor to mediate the process.