title: Animal models for osteoporosis.
abstract: The major types of osteoporosis in humans are postmenopausal osteoporosis, disuse osteoporosis, and glucocorticoid-induced osteoporosis. Animal models for postmenopausal osteoporosis are generated by ovariectomy. Bone loss occurs in estrogen deficiency due to enhanced bone resorption and impaired osteoblast function. Estrogen receptor α induces osteoclast apoptosis, but the mechanism for impaired osteoblast function remains to be clarified. Animal models for unloading are generated by tail suspension or hind limb immobilization by sciatic neurectomy, tenotomy, or using plaster cast. Unloading inhibits bone formation and enhances bone resorption, and the involvement of the sympathetic nervous system in it needs to be further investigated. The osteocyte network regulates bone mass by responding to mechanical stress. Osteoblast-specific BCL2 transgenic mice, in which the osteocyte network is completely disrupted, can be a mouse model for the evaluation of osteocyte functions. Glucocorticoid treatment inhibits bone formation and enhances bone resorption, and markedly reduces cancellous bone in humans and large animals, but not consistently in rodents.
authors: Department of Cell Biology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan. Electronic address: komorit@nagasaki-u.ac.jp.
authors: Toshihisa
authors: T
authors: Komori
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001862:Bone Resorption; D004195:Disease Models, Animal; D047628:Estrogen Receptor alpha / Q000235:genetics; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage; D019417:Hindlimb Suspension; D006801:Humans; D010006:Osteoblasts / Q000187:drug effects / Q000473:pathology; D010010:Osteoclasts / Q000187:drug effects / Q000473:pathology; D010024:Osteoporosis / Q000209:etiology* / Q000235:genetics / Q000276:immunology / Q000473:pathology; D010052:Ovariectomy; D013045:Species Specificity
chemical_list: D047628:Estrogen Receptor alpha; D005938:Glucocorticoids
keywords: Estrogen; Glucocorticoid; Osteocyte; Osteoporosis; Sympathetic nerve; Unloading