2型糖尿病大鼠肠系膜动脉平滑肌细胞大电导钙激活钾通道α、β1亚基蛋白及mRNA表达水平变化

目的  探讨2型糖尿病（T2DM）大鼠肠系膜动脉平滑肌细胞大电导钙激活钾通道（BKCa）α、β1亚基蛋白及mRNA表达水平变化，从分子水平阐明T2DM大鼠肠系膜动脉平滑肌细胞膜BKCa通道活性改变的具体机制，为T2DM的综合治疗提供新靶点；为特异性针对此环节的药物研发提供实验依据。方法  SD大鼠高糖高脂饮食1个月后腹腔注射链脲菌素STZ（25 mg/kg）建立T2DM大鼠模型。免疫印记法和实时定量聚合酶链式反应测定肠系膜动脉BKCa通道α和β1亚基的蛋白和mRNA表达水平。结果  ①免疫印迹结果显示：模型组在第8周和第12周肠系膜动脉大电导钙激活钾通道（BKCa）α蛋白相对表达量分别为（1.093±0.251）和（0.921±0.153），与对照组比较差异无统计学意义（P >0.05）；β1蛋白相对表达量分别为（0.334±0.200）和（0.193±0.310），与对照组比较差异有统计学意义（P <0.05）。②实时定量聚合酶链式反应结果显示，模型组在第8周和第12周肠系膜动脉BKCa α亚基mRNA的表达分别为（1.15±0.03）和（0.92±0.04），与对照组比较差异无统计学意义（P >0.05）；β1亚基mRNA的表达分别为（0.47±0.10）和（0.37±0.12），与对照组比较差异有统计学意义（P <0.05）。结论  T2DM大鼠肠系膜动脉BKCa β1亚基蛋白和mRNA表达在8周及12周明显降低。

Expression changes of α, β1 subunit protein and mRNA of large-conductance calcium-activated potassium channels in mesenteric arterial smooth muscle cells of type 2 diabetes mellitus rats

Objective To explore the expression changes of α and β1 subunit protein and mRNA of the large-conductance calcium-activated potassium channels (BK Ca) in mesenteric arterial smooth muscle cells of type 2 diabetes mellitus (T2DM) rats, and to elucidate the specific mechanism of BK Ca channel activity in T2DM mesenteric arterial smooth muscle cells from the molecular level, and to provide new targets for the comprehensive treatment of T2DM and the experimental basis for the specific needle to the drug research and development. Methods After one-month high glucose and high fat diet, SD rats were treated with intraperitoneal injection of streptozotocin (STZ 25 mg/kg) to establish a rat model of type 2 diabetes mellitus. Western blot and real-time PCR were used to detect α and β1 subunit protein and mRNA expression levels. Results Western blot showed that α subunit protein expressions of mesenteric artery BK Ca channel in model group at 8 and 12 weeks were (1.093 ± 0.251) and (0.921 ± 0.153)respectively, and had no statistical significance compared with the control group (P > 0.05). Expressions of β1 subunit protein in model group at 8 and 12 weeks were (0.334 ± 0.200) and (0.193 ± 0.310) respectively. There was statistical significance compared with the control group (P < 0.05). Real-time quantitative PCR results showed that α subunit mRNA expressions of mesenteric artery BK Ca channel in model group at 8 and 12 weeks were (1.15 ± 0.03) and (0.92 ± 0.04), and had no statistical significance compared with the control group (P > 0.05). Expressions of β1 subunit mRNA were (0.47 ± 0.10) and (0.37 ± 0.12), which were significantly reduced comparing with the control group (P < 0.05). Conclusions Expressions of β1 subunit protein and mRNA of BK Ca channel in mesenteric artery are decreased significantly in T2DM rats at 8 and 12 weeks.