STZ诱导的糖尿病对骨密度和血清睾酮的影响(英文)

Effect of STZ-induced diabetes on bone mineral density and testosterone

探讨链脲霉素（STZ）诱导的糖尿病对大鼠骨代谢的影响及机制．雄性Wistar大鼠随机分成3组：正常组（n=6），糖尿病组（n=5）和胰岛素治疗糖尿病组（n=5）．大鼠尾静脉一次性注射STZ（50mg／kg体重），选择空腹12h血糖大于12mmol／L的大鼠为本实验所需的糖尿病模型．治疗组大鼠每天在同一时间给予1．8～2．2U的胰岛素，实验周期为32d．采用双能X线骨吸收法（DEXA）测定股骨密度，ELISA法测定血清雄性激素睾酮水平，生化分析仪测定血清碱性磷酸酶、钙、磷浓度．糖尿病大鼠的股骨密度和血清睾酮均显著低于正常组（P〈0．01），血清总碱性磷酸酶明显高于正常组和胰岛素治疗组（P〈0．01）．3组之间血钙和血磷的水平无明显差异．胰岛素治疗后糖尿病大鼠的骨密度、血清睾酮与总碱性磷酸酶得到明显的改善．糖尿病严重影响骨密度，胰岛素缺乏及雄性激素降低是导致糖尿病性骨质疏松的重要原因．胰岛素治疗能预防骨流失和提高血清睾酮浓度．

To investigate the effect of diabetes mellitus on bone metabolism, bone mineral density（BMD） and serum testosterone were studied in STZ-induced diabetic male rats. Male Wistar rats were randomly divided into control group （ n = 6）, diabetic group （ n = 5 ） and insulin-treated diabetic group （ n = 5 ）. Diabetes was intravenously induced by injection of streptozotocin（STZ, 50mg/kg body weight）, confirmed by 12h fasting blood glucose concentration（ 12mmol/L）. The treatment group was subcutaneously injected with protamine zinc insulin（ 1.8- 2.2U/animal）at the same time every day. The experiment lasted 32d. Femoral BMD was determined by dual-energy X-ray absorptiometry（DEXA）. Serum testosterone was detected by Enzyme-linked Immunosorbent Assay（ELISA）kit. Total alkaline phosphatase（ALP）, calcium （Ca）and phosphorus（P）in serum were measured by bio-machine. Femoral BMD in diabetic group was significantly lower than that in control（ P 〈 0.01 ） but reserved by insulin treatment. Testosterone in serum was also reduced in diabetic rats（ P 〈 0.01 ） and normalized by insulin treatment .The serum ALP concentration was markedly higher in diabetics（ P 〈 0.01 ） compared with the controls and prevented by insulin treatment. However, no significant differences were observed in serum Ca and P among three groups. Our results suggest that BMD is seriously affected by diabetes. Insulin deficiency and testosterone decrease are important causes of diabetic osteoporosis, And insulin treatment prevented bone loss and testosterone depression.