Effect of bone mass, microarchitecture and impact direction on biomechanical properties of bone in ovariectomy-induced osterporotic rats

ObjectiveTo observe relationship between biomechanical change and bone mass, microarchitecture, impact direction in osterporotic rats.MethodsFifty 6-7 month old Wister rats were subjected to 25 for ovariectomy(OVX) and 25 as control. All rats were sacrificed after 12 weeks. Whole body bone mineral density(BMD) and BMD at femur and lumber spine was measured. Biomechanical test was conducted for femur and lumber spine. Partial femur and lumber spines were assayed by immunohistochemical staining.ResultBMD in whole body, femur and lumber spines significantly decreased in OVX rats. Compressive load of lumber spines and failure load tested at 20° angle of right femur was significantly lower in OVX rats. But structural mechanics of 0° angle of left femur was not significantly different between two groups. Mechanics of materials significantly decreased in OVX rats. Immunostaining shows that trabecular bone was lost obviously in OVX rats.ConclusionChange of bone mass and microarchitecture was more obvious in OVX rats. Bone mass, microarchitecture, impact direction significantly affect bone biomechanical property.