title: Prostaglandin E2 adds bone to a cancellous bone site with a closed growth plate and low bone turnover in ovariectomized rats.
abstract: The objects of this study were to determine the responses of a cancellous bone site with a closed growth plate (the distal tibial metaphysis, DTM) to ovariectomy (OVX) and OVX plus a prostaglandin E2 (PGE2) treatment, and compare the site's response to previous findings reported for another site (the proximal tibial metaphysis, PTM). Thirty-five 3-month-old female Sprague-Dawley rats were divided into five groups: basal, sham-OVX, and OVX + 0, +1, or +6 mg PGE2/kg/d injected subcutaneously for 3 months and given double fluorescent labels before sacrifice. Cancellous bone histomorphometric analyses were performed on 20-microns-thick undecalcified DTM sections. Similar to the PTM, the DTM showed age-related decreases in bone formation and increases in bone resorption, but it differed in that at 3 months post-OVX, there was neither bone loss nor changes in formation endpoints. Giving 1 mg PGE2/kg/d to OVX rats prevented most age-related changes and maintained the bone formation histomorphometry near basal levels. Treating OVX rats with 6 mg PGE2/kg/d prevented age-related bone changes, added extra bone, and improved microanatomical structure by stimulating bone formation without altering bone resorption. Furthermore, after PGE2 administration, the DTM, a cancellous bone site with a closed growth plate, increased bone formation more than did the cancellous bone in the PTM.
authors.affiliation: Radiobiology Division, University of Utah School of Medicine, Salt Lake City.
authors.forename: Y F
authors.initials: YF
authors.lastname: Ma
authors.forename: H Z
authors.initials: HZ
authors.lastname: Ke
authors.forename: W S
authors.initials: WS
authors.lastname: Jee
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001846:Bone Development / Q000187:drug effects*; D001862:Bone Resorption / Q000188:drug therapy; D015232:Dinoprostone / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D006132:Growth Plate / Q000187:drug effects*; D008856:Microscopy, Fluorescence; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013977:Tibia / Q000033:anatomy & histology / Q000187:drug effects
chemical_list: D015232:Dinoprostone