The effects of gonadotropin-releasing hormone agonist (buserelin) and orchidectomy on bone turnover markers and histomorphometry in rats

This study aimed to compare the skeletal effect between GnRH agonist therapy and orchidectomy in male rats assessed using serum turnover markers and bone histomorphometry. Three-month-old male Sprague-Dawley rats (n = 46) were divided into three experimental arms, baseline, buserelin, and orchidectomy. In the buserelin arm, the rats received a daily subcutaneous injection of either normal saline or buserelin acetate at 25 mu g/kg or 75 mu g/kg. In the orchidectomy arm, the rats were either sham-operated or orchidectomized. The rats were euthanized after the three-month treatment. Blood was collected for the evaluation of bone turnover markers. Femurs were harvested for bone histomorphometry examination. A significant increase in serum C-telopeptide of type 1 collagen was observed in the orchidectomized group compared with the sham group (p < .05). Structural histomorphometry analysis showed that both buserelin (25 mu g/kg and 75 mu g/kg) and orchidectomy significantly decreased the trabecular bone volume, number and significantly increased trabecular separation in rats compared with their respective controls (p < .05). Osteoclast number and eroded surface were significantly increased in both buserelin (25 mu g/kg and 75 mu g/kg) and orchidectomized group compared with their respective controls (p < .05). As a conclusion, buserelin causes deterioration of bone microarchitecture and increased bone resorption similar to orchidectomy after three months.