title: Risedronate plus prostaglandin E2 is superior to prostaglandin E2 alone in maintaining the added bone after withdrawal in a non-growing bone site in ovariectomized rats.
abstract: Effects of risedronate and prostaglandin E2 (PGE2) alone or in combination on the distal tibia, a non-growing bone site with closed epiphysis at 3 months of age, were studied in ovariectomized (ovx) rats. Six-month-old Sprague-Dawley female rats were either ovx or sham-ovx. Rats were treated immediately after operation either with risedronate (5 micrograms/kg/2x/wk), PGE2 (6 mg/kg/d), or risedronate+PGE2 for 60 days (on-groups) and followed by 60 days without treatment (off-groups). Trabecular area, width and numbers were determined in metaphyseal cancellous bone of the distal tibia. No significant bone loss or structural changes were observed in the distal tibial metaphysis after 120 days of ovx. Risedronate alone did not produce any effect on bone mass during the treatment and the withdrawal periods. PGE2 alone increased the trabecular bone mass associated with thickened trabeculae and increased trabecular numbers. However, some of the newly formed bone was lost at the end of 60 days withdrawal. Combination of risedronate and PGE2 treatment added the same amount of bone mass as PGE2 alone, and the added new bone was maintained during the 60 days withdrawal. These results indicate that treatment with risedronate and PGE2 can preserve the anabolic effect of PGE2 on bone mass for at least 60 days after treatment.
authors.affiliation: Radiobiology Division, University of Utah, Salt Lake City 84112, USA.
authors.forename: H H
authors.initials: HH
authors.lastname: Liang
authors.forename: Y F
authors.initials: YF
authors.lastname: Ma
authors.forename: W S
authors.initials: WS
authors.lastname: Jee
authors.forename: Z
authors.initials: Z
authors.lastname: Pan
authors.forename: R B
authors.initials: RB
authors.lastname: Setterberg
authors.forename: J E
authors.initials: JE
authors.lastname: McOsker
authors.forename: X J
authors.initials: XJ
authors.lastname: Li
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001851:Bone Diseases, Metabolic / Q000188:drug therapy*; D015232:Dinoprostone / Q000494:pharmacology*; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination; D012968:Etidronic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000068296:Risedronic Acid; D013977:Tibia / Q000187:drug effects*
chemical_list: D015232:Dinoprostone; D000068296:Risedronic Acid; D012968:Etidronic Acid