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Titolo:
Bipedal stance exercise enhances antiresorption effects of estrogen and counteracts its inhibitory effect on bone formation in sham and ovariectomized rats
Autore:
Chen, JL; Yao, W; Frost, HM; Li, CY; Setterberg, RB; Jee, WSS;
Indirizzi:
Univ Utah, Div Radiobiol, Salt Lake City, UT 84108 USA Univ Utah Salt Lake City UT USA 84108 obiol, Salt Lake City, UT 84108 USA So Colorado Clin, Dept Orthoped Surg, Pueblo, CO USA So Colorado Clin Pueblo CO USA Clin, Dept Orthoped Surg, Pueblo, CO USA
Titolo Testata:
BONE
fascicolo: 2, volume: 29, anno: 2001,
pagine: 126 - 133
SICI:
8756-3282(200108)29:2<126:BSEEAE>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
MECHANICAL STRAIN; CANCELLOUS BONE; MINERAL DENSITY; 17-BETA-ESTRADIOL REPLACEMENT; TREADMILL EXERCISE; TURNOVER; CELLS; HISTOMORPHOMETRY; RESORPTION; RECEPTORS;
Keywords:
estrogen; raised cage; bone turnover; bone formation; histomorphometry;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
30
Recensione:
Indirizzi per estratti:
Indirizzo: Yao, W Univ Utah, Div Radiobiol, 729 Arapeen Dr,Suite 2334, Salt Lake City, UT 84108 USA Univ Utah 729 Arapeen Dr,Suite 2334 Salt Lake City UT USA 84108 USA
Citazione:
J.L. Chen et al., "Bipedal stance exercise enhances antiresorption effects of estrogen and counteracts its inhibitory effect on bone formation in sham and ovariectomized rats", BONE, 29(2), 2001, pp. 126-133

Abstract

In this study we employed a raised cage model in combination with estrogento observe their effects on the proximal tibial metaphysis (PTM) and tibial shaft (TX) in sham-operated or ovariectomized rats. A total of 105 6-month-old female Sprague-Dawley rats were used in the study. Bilateral sham ovariectomy or ovariectomy was performed at day 0 and the rats were housed in normal height or raised cages (RCs) and injected subcutaneously twice per week with 10 mug/kg of 17 beta -estradiol (E-2) or vehicle for 4 and 8 weeks. Because the time course of bone loss or bone gain distribution was not uniform in the metaphyses of the tibia, we subdivided the PTM into three zones (medial, central, and lateral) to observe the different bone loss or bonegain patterns after ovariectomy and/or raised cages. We found that: (1) E-2 alone did not alter bone area or architecture in sham rats, whereas RC alone increased trabecular thickness and area of PTM, but had no effects on TX; (2) Ovx induced most bone loss from the central zone of the PTM and endocortical surface of TX, accompanied by decreased trabecular number and increased bone resorption; (3) E-2 alone prevented ovx-induced bone loss by preserving trabecular number and depressing bone resorption; (4) RC alone partially compensated for bone loss following ovx by thickening the surviving trabeculae in lateral and medial zones, and tended to stimulate bone formation and decrease bone resorption; and (5) RC Plus E2 increased trabecular bone area by having an additive effect on bone resorption and bone turnover. RCs helped to prevent the depressive effect of estrogen on periosteal bone formation. In conclusion, early and rapid bone loss occurred in the centralzone of the metaphysis and endocortical surface after ovx. Estrogen replacement therapy prevented this loss. Raised cages partially compensated for bone loss following ovx by thickening the trabeculae in the lateral area of the metaphysis and decreased endocortical erosion. Combination treatment added bone to the PTM and prevented the decrease of periosteal bone formationafter estrogen administration. (C) 2001 by Elsevier Science Inc. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 12:39:13