Abstract: ObjectiveTo observe the effect of early administration of alendronate on bone mineral density and biomechanical properties of the femur of spinal cord injuried rats.Methods36 3-month-old female SD rats were randomly divided into the Sham group, SCI group and SCI+ALN group. Rats in the Sham group underwent a sham procedure. Rats in the SCI group and in SCI+ALN group underwent spinal cord transection at the level of the tenth thoracic vertebra. Rats in the SCI+ALN group were injected with alendronate intraperitoneally 1 week after SCI, three times a week. All rats were sacrificed 8 week after operation. Bone mineral density and biomechanical properties of the femur were measured, respectively.ResultsBone mineral density and biomechanical properties of the femur changed significantly after spinal cord transection. After the treatment of alendronate injection, bone mineral density of the femur in the SCI+ALN group was significantly increased compared with that of the SCI group(P<0.01). Elastic loading and maximal loading of the femur in the SCI+ALN group was significantly increased compared with that of the SCI group(P<0.01). Maximal stress was significantly increased compared with that of the SCI group(P<0.05). ConclusionThe rats 8 week after spinal cord transection can be used in osteoporotic research following SCI. Early administration of ALN after SCI can inhibit bone resorption, improve biomechanical properties of the femur of spinal cord injured rats so as to prevent the development of osteoporosis and osteoporotic fracture.

Key words: alendronate, spinal cord injury, osteoporosis, bone mineral density, biomechanical, rats