title: Differences in vertebral, tibial, and iliac cancellous bone metabolism in ovariectomized rats.
abstract: Bone histomorphometry is usually performed on the iliac bone in humans and the tibia or vertebrae in rats. Bone metabolism differences among skeletal sites may be problematic when translating experimental results from rats to humans, but data on such differences in rats are lacking. Therefore, we examined the differences in bone structure and metabolism among skeletal sites using the lumbar vertebra (LV), tibia, and iliac bone obtained from ovariectomized or sham-operated rats preoperatively and at various times from 3 days to 26 weeks postoperatively. The trabeculae were thicker in the LV, where bone metabolism was less active than at other sites, and numerous fine trabeculae were observed in the tibia, where bone metabolism was more active. The iliac bone structure and metabolism were intermediate between those of the tibia and LV. Ovariectomy induced lower bone volume and higher bone metabolism in all skeletal sites, but the changes were greatest and occurred earliest in the tibia, followed by the iliac bone and then LV. Ovariectomy caused changes in bone metabolic markers, which occurred earlier than those in bone tissue. Activation frequency (Ac.f) increased after ovariectomy. At week 26 in ovariectomized rats, Ac.f was highest in the tibia (3.13 N/year) but similar between iliac bone (0.87 N/year) and LV (1.39 N/year). Ac.f is reportedly 0.3-0.4 N/year in the iliac bone of postmenopausal women, suggesting that bone turnover in rats is several times higher than in humans. The reference values reported here are useful for translating experimental results from rats to humans.
authors.affiliation: Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni, Shizuoka, 410-2321, Japan. shimomura.ac@om.asahi-kasei.co.jp.
authors.forename: Aya
authors.initials: A
authors.lastname: Takakura
authors.affiliation: Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni, Shizuoka, 410-2321, Japan.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Takao-Kawabata
authors.affiliation: Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni, Shizuoka, 410-2321, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Isogai
authors.affiliation: Pharmaceutical Department, Kureha Special Laboratory, 3-26-2 Hyakunincho, Shinjuku-ku, Tokyo, 169-8503, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kajiwara
authors.affiliation: Pharmaceutical Department, Kureha Special Laboratory, 3-26-2 Hyakunincho, Shinjuku-ku, Tokyo, 169-8503, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Murayama
authors.affiliation: Department of Oral Anatomy, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan.
authors.forename: Sadakazu
authors.initials: S
authors.lastname: Ejiri
authors.affiliation: Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni, Shizuoka, 410-2321, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Ishizuya
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D006801:Humans; D007085:Ilium / Q000378:metabolism* / Q000473:pathology; D008159:Lumbar Vertebrae / Q000378:metabolism* / Q000473:pathology; D010052:Ovariectomy / Q000009:adverse effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013977:Tibia / Q000378:metabolism* / Q000473:pathology
chemical_list: D015415:Biomarkers
keywords: Bone metabolism; Histomorphometry; Ovariectomy; Rat