Effects of neurectomy and tenotomy on the bone mineral density and strength of tibiae

The right hindlimbs of 5 or 6-week old Wistar male rats were sciatic/femora l neurectomized, tenotomized or sham operated. The rats were sacrificed 2 w eeks after the surgery and the tibiae were removed. pQCT measurement was pe rformed on total, cortical, and trabecular bone separately at different reg ions. Reduction of the bone mineral density by unloading was observed more significantly at metaphysis than at diaphysis due to histological heterogen eity between metaphysis and diaphysis; metaphysis is rich in trabecular bon e and diaphysis is abundant in cortical bone. Trabecular bone might be more sensitive to unloading because the reduction rate of volumetric bone miner al density in trabecular bone was approximately 10 times and 3 times larger than that of cortical bone in both neurectomy and tenotomy rats, respectiv ely. Unloading also reduced the cross-sectional area and stress strain inde x at metaphysis. (C) 2001 Elsevier Science Ltd. All rights reserved.