The Immobilized Adult Cancellous Bone Site in a Growing Rat as an Animal Model of Human Osteoporosis

A review of the widely used rat osteopenic models finds the ovariectomy-induced bone loss model to be unsuitable for human osteoporosis. Only the rat immobilized distal tibia1 spongiosa models of transient state (high bone turnover, resorption, and formation) and steady state (low bone turnover resorption and formation-induced cancellous bone loss with resorption and formation histodynamics similar to man models in 4 mo or older rats) are suitable models for human osteoporosis. No rat adult cortical bone model exists. However, suitable cortical bone osteopenia models as well as different models of adult cancellous bone loss can be developed with studies of 18 mo or older rats. If the latter is achievable, then a second larger remodeling species is not needed for preclinical evaluation of agents used in the prevention or treatment of postmenopausal osteoporosis. (The J Histotechnol 20:201, 1997)