ABSTRACT
Postinenopausal bone resorption is influenced by a variety of factors that result in increased activation of osteoclasts. Osteoblasts were reported to secrete an osteoclast inhibiting protein named osteoprotegerin and this secretion was found to be influenced by the estrogen hormone level. So, the aim of this study was to investigate osteoprotegerin protein expression in human female bone and assess its relation to structural bone changes occurring after menopause. This study was conducted on 34 specimens from the iliac crest of female subjects undergoing bone grafts after taking their consent. They were divided into 3 groups. Females of group. I were in the premenopausal period. Those of group II were um the early postmenopausal period while those of group ill were in the late postmenopausal period. Osteoprotegerin protein expression was seen mainly in the cytoplasm of osteogenic cells and osteoblasts lining the bone trabeculae of the iliac crests. This expression was significantly higher in the premenopausal women as compared to both postmenopausal groups with no significant difference between early and late postmenopausal groups. Specimens taken from postmenopausal women showed significant decrease in the trabecular thickness together with significant increase in the trabecular separation and eroded surface. These changes were more prominent In late postmenopause. There was a significant positive correlation between osteoprotegerin expression amid serum estradiol, bone volume and trabecular thickness. Meanwhile, there was a significant negative correlation between osteoprotegerin protein expression and trabecular separation and eroded surface. It was concluded that decrement of osteoprotegerin plays an important role in the pathogenesis of postmenopausal osteoporosis and it is recommended to use osteoprotegerin in future therapeutic interventions in osteoporosis