低浓度乙醇对糖尿病大鼠心肌损伤后线粒体融合素2表达的影响

目的：探讨低浓度乙醇对糖尿病大鼠心肌损伤后线粒体融合素2（mfn2）表达的影响。方法：糖尿病大鼠模型采用链脲佐菌素55 mg/kg腹腔注射，分为正常对照组（Control组），糖尿病组（DM组）和糖尿病+乙醇组（DM+EtOH组）（n=6）；糖尿病+乙醇组于造模成功1周后给予2.5%乙醇日常饮用，1周后改为5%的乙醇持续至8周，8周后行离体心脏灌流，测定心室血流动力学指标，应用自动生化分析仪测定血清乳酸脱氢酶（LDH）和天门冬氨酸转移酶（AST）的水平。Western blot测定左心室组织线粒体融合素2（mfn2）蛋白表达，免疫组化测定心肌组织mfn2蛋白表达。结果：与control组大鼠心肌相比，DM组大鼠心率、左室发展压、左室做功下降，左室舒张末压抬高，血清LDH及AST升高明显，心室mfn2蛋白表达降低；与DM组大鼠心肌相比，DM+EtOH组明显促进心率、左室发展压、左室做功的恢复，降低左室舒张末压，同时降低LDH的水平和AST的释放，mfn2的蛋白表达增高。结论：糖尿病大鼠心肌损伤时，心肌mfn2表达降低；低浓度乙醇增强mfn2在心肌组织中的表达，提示mfn2的增加可能参与低浓度乙醇对糖尿病诱发的心肌损伤的保护作用。

Effects of low-concentrations alcohol consumption on the expression of mitofusin-2 in myocardial injury of diabetic rats

Objective:To observe the effects of low-concentrations of alcohol consumption on the expression of mitofusin-2 (mfn2) in myocardial injury of diabetic rats. Methods:Diabetic rat model was simulated by intraperitoneal injection of 55 mg/kg streptozotocin (STZ) and divided into control group, diabetes mellitus(DM) and diabetes+ethanol (DM+EtOH) groups (n=6). When diabetic model was suc-ceed, daily consumption of 2.5% ethanol was used in ethanol+diabetic group after one week, then changed to 5% ethanol continued until 8 weeks. Eight weeks after the modeling, heart perfusion ex vivo. The ventricular hemodynamic parameters were recorded, the serum levels of lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) were determined by automatic biochemistry analyzer, the mfn2 protein ex-pression of left anterior myocardium was evaluated by Western blot and immunohistochemistry. Results:Compared with control group, the left ventricular development pressure (LVDP), heart rate (HR) and rate pressure product (RPP) were decreased, however, left ventricular and diastolic pressure (LVEDP) and LDH, AST release were increased, the expression of mfn2 protein was decreased in DM group. Compared with DM group, LVDP, HR and RPP and the expression of mfn2 protein were increased, LVEDP and LDH, AST were decreased in DM+E-tOH group. Conclusion:The expression of mfn2 protein was decreased in myocardial injury of diabetic rats, low-concentrations of alcohol consumption increased the expression of mfn2. It suggests that mfn2 may be participated in the cardiac protective role of low-concentrations al-cohol intervene in diabetic rat.