Effects of estradiol, calcitriol and both treatments combined on bone histomorphometry in rats with chronic kidney disease and ovariectomy

Background: The aim of this experimental study was to analyze the histomorphometric changes observed when using different doses of estradiol, calcitriol and both treatments combined, in rats with both chronic kidney disease (CKD) and ovariectomy (OVX). Methods: Six groups of rats with CKD+OVX were treated for 8 weeks with placebo, with different doses of 17 beta-estradiol (E-2), with calcitriol or with both treatments combined (E-2+calcitriol). Histomorphometric studies were carried out at the proximal tibia segment. Results: All groups that received active treatments showed a trabecular bone volume similar to those of rats with normal ovarian function. Treatment with E-2 was effective, E-2-10 diminished osteoid and eroded surfaces, and E-2-30 was able to achieve a bone remodeling similar to that of the normal group. Calcitriol proved to have a positive effect on bone microarchitecture, achieving normal trabecular connectivity. The combined treatment with E-2-30+calcitriol was the most effective treatment as it was not only capable of achieving normal trabecular remodeling and connectivity, but also normal trabecular bone volume. Conclusions: E-2 and calcitriol seem to have independent effects on cancellous bone turnover in rats with CKD+OVX. In rats with chronic kidney disease and ovariectomy, these two agents are able to produce additive effects on bone and offer additional advantages as opposed to the use of both drugs independently. (C) 2007 Elsevier Inc. All rights reserved.