褪黑素抗糖尿病所致心肌损伤的作用研究

目的探讨褪黑素(melatonin,MLT)在链脲佐菌素(streptozotocin,STZ)诱导的糖尿病(DM)大鼠心肌损伤中发挥的作用。方法将30只成年雄性SD大鼠随机分为对照组、DM模型组和MLT治疗组。大鼠连续5 d腹腔注射STZ(50 mg/kg)诱导糖尿病大鼠模型,造模成功后腹腔注射MLT(30 mg/kg)治疗8周。8周后,尾静脉取血检测大鼠空腹血糖和血清胰岛素水平;心脏超声检测各组大鼠心脏功能;HE和Masson染色检测心肌组织形态变化;原位末端标记法(TUNEL)检测心肌细胞凋亡;ELISA试剂盒检测血清和心肌组织氧化应激相关体液因子水平和炎症因子水平。结果与对照组相比,糖尿病大鼠血糖升高、血清胰岛素水平降低,心脏超声结果显示糖尿病大鼠心脏收缩舒张功能降低,HE和Masson染色显示糖尿病大鼠心肌细胞形态紊乱、胶原聚集,TUNEL法检测结果显示糖尿病大鼠心肌细胞凋亡增加,ELISA法检测结果显示糖尿病大鼠血清MDA水平明显增加、SOD、CAT水平明显减少,炎症因子TNF-α和IL-1β水平明显增加;与DM模型组相比,MLT治疗组大鼠血糖水平明显降低、血清胰岛素水平明显增加,治疗组大鼠心脏收缩和舒张功能、心肌形态的紊乱和胶原的产生均有所改善;心肌细胞凋亡明显减少,血清的MDA水平减少、SOD、CAT的水平增加,TNF-α和IL-1β的水平也有明显减少。结论 MLT具有减轻糖尿病所致心肌损伤的作用,其作用机制是否与其发挥抗氧化活性尚需进一步研究证实。

Effect of melatonin on myocardial injury caused by diabetes mellitus

AIM To study the effect of melatonin (MLT) on myocardial damage caused by diabetes mellitus induced by streptozotocin (STZ). METHODS SD rats were randomly divided into a control group, a diabetes mellitus group (DM), and a medicated group. The diabetes mellitus model was established by intraperitoneal injection of STZ (50 mg/kg) for 5 days. After the DM model was established, the medicated group was treated with melatonin (30 mg/kg) for 8 weeks. Fasting blood glucose (FBG) was measured by Roche glucometer, serum insulin levels were measured by kit, and cardiac function was measured by echocardiography. Heart histology and morphology was observed with HE and Masson trichrome stain. Myocardial apoptosis was detected by TUNEL and humoral factors in serum were measured by Elisa kit. RESULTS In the MLT group, FBG decreased, serum insulin increased, cardiac systolic and diastolic functions improved, ruined form and frame of myocardium ameliorated, myocardial apoptosis decreased, serum malonaldehyde, TNF-α, IL-1β decreased, and serum superoxide dismutase and catalase increased,compared with those in the DM group. CONCLUSION Melatonin ameliorates myocardial damage caused by diabetic mellitus and further study is needed to demonstrate the underlying mechanism.