Effect of simvastatin on bone mineral density and biomechanical properties of ovariectomized rats / 中国组织工程研究

ABSTRACT

BACKGROUND:Osteoporosis and its complications severely threaten the elder’s health. Simvastatin, widely accepted as a lipid-lowering drug, is reported to potentialy promote bone formation, but it is in debate when oraly administered, and there is no evidence to support whether this is due to the region difference. OBJECTIVE:To investigate the effect of oraly administered simvastatin on bone mass and biomechanical properties of the femur and vertebrae in osteopenia rats induced by ovariectomy (OVX). METHODS: Twenty-four 6-month-old female Sprague-Dawley rats were subjected to OVX+oraly administered saline vehicle (OVX group,n=8), OVX+oraly administered simvastatin (5 mg/kg/d; intervention group,n=8) or sham surgery (sham group,n=8). After 8 weeks of treatment, al rats were sacrificed and the level of procolagen type I N-terminal propeptide in blood serum was assessed by ELISA. Bone mineral density was determined in the L5 vertebra and left femur using dual-energy X-rays. Furthermore, the biomechanical properties of the L4 vertebra and right femur, including maximum load and elastic modulus, were detected by compression testing and three-point bending test, respectively. RESULTS AND CONCLUSION: The serum level of procolagen type I N-terminal propeptide in the sham group was significantly lower than that in the other two groups. OVX rats showed significantly lower bone mineral density in both the L5 vertebra and left femur than sham rats (P < 0.05). Rats in the intervention group showed higher bone mineral density than those in the OVX group, with statisticaly significant difference in the L5 vertebra (P < 0.05), but insignificant difference in the femur. Maximum load and elastic modulus of the L4 vertebra in the OVX group were significantly lower than those in the sham and intervention group. Markedly lower elastic modulus of the femur was found in the OVX group than the sham and intervention groups. These findings demonstrate that simvastatin treatment can partialy prevent bone loss in OVX rats with more notable effect on the vertebrae than the femur, and for this model, the vertebra is superior to the femur used in biomechanical test.