Effect of 17ß-estradiol or alendronate on the bone densitometry, bone histomorphometry and bone metabolism of ovariectomized rats

Author(s)

L.H.B.C. da Paz ^[1] ; V. de Falco ^[2] ; N.C. Teng ^[3] ; L.M. dos Reis ^[4] ; R.M.R. Pereira ^[5] ; V. Jorgetti ^[6]

Affiliation

^[1] Universidade de São Paulo. Faculdade de Medicina. Departamento de Reumatologia

^[2] Universidade de São Paulo. Faculdade de Medicina. Departamento de Reumatologia

^[3] Universidade de São Paulo. Faculdade de Medicina. Departamento de Nefrologia - Brasil

^[4] Universidade de São Paulo. Faculdade de Medicina. Departamento de Nefrologia - Brasil

^[5] Universidade de São Paulo. Faculdade de Medicina. Departamento de Reumatologia

^[6] Universidade de São Paulo. Faculdade de Medicina. Departamento de Nefrologia - Brasil

• Document type: Journal article
• Source: Brazilian Journal of Medical and Biological Research; v. 34, n. 8, p. 1015-1022, 2001-08-00.

Abstract

The objective of the present study was to evaluate the effect of 17ß-estradiol or alendronate in preventing bone loss in 3-month-old ovariectomized Wistar rats. One group underwent sham ovariectomy (control, N = 10), and the remaining three underwent double ovariectomy. One ovariectomized group did not receive any treatment (OVX, N = 12). A second received subcutaneous 17ß-estradiol at a dose of 30 µg/kg for 6 weeks (OVX-E, N = 11) and a third, subcutaneous alendronate at a dose of 0.1 mg/kg for 6 weeks (OVX-A, N = 8). Histomorphometry, densitometry, osteocalcin and deoxypyridinoline measurements were applied to all groups. After 6 weeks there was a significant decrease in bone mineral density (BMD) at the trabecular site (distal femur) in OVX rats. Both alendronate and 17ß-estradiol increased the BMD of ovariectomized rats, with the BMD of the OVX-A group being higher than that of the OVX-E group. Histomorphometry of the distal femur showed a decrease in trabecular volume in the untreated group (OVX), and an increase in the two treated groups, principally in the alendronate group. In OVX-A there was a greater increase in trabecular number. An increase in trabecular thickness, however, was seen only in the OVX-E group. There was also a decrease in bone turnover in both OVX-E and OVX-A. The osteocalcin and deoxypyridinoline levels were decreased in both treated groups, mainly in OVX-A. Although both drugs were effective in inhibiting bone loss, alendronate proved to be more effective than estradiol at the doses used in increasing bone mass. (AU)