Changes on the bone histomorphometry and the biomechanical property of canallous bone in ovariectomized rats

Object To present the changes of serum bone-alkaline phosphatase,serum tartrate-resistant acid phosphatase,cancellous bone histomorphometry,biomechanical property and bone mineral density(BMD)in ovariectomized rats.Methods 30 female SD rats at 7-12 months of old were randomized to three groups:sham,OVX and OVX+Nylestriol.After operation,rats were treated with drug starting at 45 days for 90days.Double in v ivo fluorocrome labeling was administered to all rats.At the end point of study,femur bones were cut and stained for bone histomorphometric analyses,serum bone-alkaline phosphatase,serum tartrate-resistant acid phosphatase,BMD and biomechanical property of femur bone and fourth lumbar vertebra(LV4)were measured.Results Bone M-load,M-strain, elastic moduli,stiffness of LV4 and trabecular bone volume(BV/TV)of femur bone in ovariectomized rats significantly increased,histomorphometry,flexible property of femur bone and the other compressive mechanic property of LV4 did not change considerably.Conclusion Bone histomorphometry and biomechanical properties are important parameters in the animal studies on osteoporosis and related pharmacodynamic observations on new drugs.The changes of bone histomorphometry are prior to that of bone biomechanical properties.