Histological and morphometric studies on the effect of alpha-lipoic acid on postovariectomy osteoporosis induced in adult female albino rats

ABSTRACT

An imbalance between bone formation and bone resorption underlined the pathogenesis of reduced bone mass in osteoporosis associated with menopause. To investigate whether alpha-lipoic acid can have any therapeutic application in treating bone loss in ovariectomized osteoporotic rats. Twenty-four adult female rats were divided into four groups a sham-operated control group [group 1], a nontreated ovariectomized group [group 2], an alpha-lipoic acid-treated ovariectomized group [group 3], and a sham-operated alpha-lipoic acid-treated group [group 4]. Histological decalcified and undecalcified distal femur specimens were prepared and histomorphometric parameters of bone resortion and bone formation were carried out. Assessment of bone resorption parameters of the distal femur metaphysis and diaphysis showed that ovariectomy in group 2 produced significant increase in mean resorption surface percentage, 28% loss in mean cortical bone thickness, and 48% loss in mean trabecular bone volume compared with controls. However, alpha-lipoic acid administration to ovariectomized rats reduced the mean resorption surface percentage to control levels. Moreover, evaluation of bone formation parameters showed that both ovariectomy in group 2 and alpha-lipoic acid administration to ovariectomized rats of group 3 caused significant increase in mean osteoid thickness and in mean osteoid surface percentage relative to control rats. Alpha-lipoic acid also completely [100%] restored mean cortical bone thickness, restored 90% of mean trabecular bone volume, and ameliorated the osteoporotic changes that accompanied ovariectomy. Alpha-lipoic acid improved the imbalance between bone resorption and bone formation, and therefore it is recommended to treat osteoporosis with alpha-lipoic acid