title: Glucocorticoid-induced secondary osteopenia in female rats: a time course study as compared with ovariectomy-induced osteopenia and response to salmon calcitonin.
abstract: Previously we reported that 8-week treatment with methylprednisolone acetate (MPA: 0.1 mg/kg, s.c., 3 days a week) of male rats caused a novel type of osteopenia whose development was prevented by salmon calcitonin (SCT) in a dose-dependent manner. In this study, to compare the MPA-inducible osteopenia with the ovariectomy (OVX)-inducible one, female rats were used instead of male rats and a time-course study of development was made. MPA treatments for 1, 2, 4 and 8 weeks histologically induced characteristic osteopenic changes in a time-dependent manner that were histomorphometrically detectable in tibiae within 4 weeks as reduced bone mass, accelerated bone resorption, and suppressed bone formation and mineralization. Node-strut analysis revealed that the connectivity of the trabecular structure remained unaffected. Such MPA-induced changes in the trabecular structure, to be defined as thinned-but-uncut, is in a good contrast with OVX-induced unthinned-but-cut structure, although the latter osteopenic changes became detectable 2 weeks earlier. Another previous finding confirmed herein was that MPA-induced osteopenia in female rats was also completely masked by SCT (10 U/kg, s.c., 5 days a week). The results indicate that the MPA-inducible secondary osteopenic model in either sex of rats would be usable for testing anti-osteopenic drugs.
authors.affiliation: Department of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Osaka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nitta
authors.forename: T
authors.initials: T
authors.lastname: Fukushima
authors.forename: H
authors.initials: H
authors.lastname: Nakamuta
authors.forename: M
authors.initials: M
authors.lastname: Koida
mesh_terms: D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D015519:Bone Density / Q000187:drug effects; D001851:Bone Diseases, Metabolic / Q000209:etiology* / Q000473:pathology / Q000517:prevention & control; D016723:Bone Remodeling / Q000187:drug effects; D001862:Bone Resorption / Q000517:prevention & control; D002116:Calcitonin / Q000494:pharmacology; D005260:Female; D005938:Glucocorticoids / Q000009:adverse effects*; D008775:Methylprednisolone / Q000009:adverse effects / Q000031:analogs & derivatives*; D000077555:Methylprednisolone Acetate; D010052:Ovariectomy / Q000009:adverse effects; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D000700:Analgesics; D005938:Glucocorticoids; D000077555:Methylprednisolone Acetate; C028815:salmon calcitonin; D002116:Calcitonin; D008775:Methylprednisolone