达格列净调节糖尿病大鼠心肌SK2蛋白表达

Dapagliflozin regulates myocardial SK2 protein expression in diabetic rats

目的探讨达格列净(dapagliflozin,Dapa)对糖尿病大鼠心肌小电导钙激活钾通道2(small conductance calcium-activated potassium channel 2,SK2通道)蛋白的影响以及可能作用机制。方法体内:高糖高脂饮食联合腹腔注射小剂量链脲佐菌素(35 mg·kg^(-1))构建2型糖尿病模型,并给予达格列净(1 mg·kg^(-1)·d^(-1))治疗干预;体外:Dapa(5μmol·L^(-1))处理原代心肌细胞并暴露于高糖(30 mmol·L^(-1));心脏超声检测各组大鼠的心功能情况;DCFH-DA荧光探针检测活性氧(reactive oxide specis,ROS)的水平;Western blot检测SK2、NOX4、p38MAPK、p-p38MAPK的蛋白表达水平。结果Dapa改善糖尿病大鼠心脏功能;Dapa降低ROS的产生;Dapa上调SK2的蛋白表达;Dapa抑制NOX4,p38MAPK及p-p38MAPK的蛋白表达;沉默NOX4基因后,Dapa降低了心肌细胞NOX4含量并促进了SK2的表达。结论Dapa可通过抑制NOX4/p38MAPK信号通路部分修复糖尿病大鼠心肌SK2的低表达。

Aim To investigate the effect of dapagliflozin on the small conductance calcium-activated potassium channel 2(SK2 channel)protein in the myocardium of diabetic rats and its possible mechanism of action.Methods In vivo:type 2 diabetes model was established by high-glucose and high-fat diet combined with intraperitoneal injection of low-dose streptozotocin(35 mg^(-1)·kg^(-1)),and dapagliflozin(1 mg·kg^(-1)·d^(-1))was given.In vitro:primary cardiomyocytes were treated with dapagliflozin(5μmol·L^(-1))and exposed to high glucose(30 mmol·L^(-1));cardiac ultrasound was used to detect the cardiac function of the rats in each group;DCFH-DA fluorescence probe was used to detect reactive oxide specis(ROS)level;Western blot was used to detect protein expression level of SK2,NOX4,p38MAPK and p-p38MAPK.Results Dapagliflozin improved cardiac function in diabetic rats.Dapagliflozin reduced ROS production.Dapagliflozin up-regulated the protein levels of SK2.Dapagliflozin inhibited the protein expressions of NOX4,p38MAPK and p-p38MAPK.After siNOX4,dapagliflozin significantly reduced NOX4 in cardiomyocytes and promoted SK2 expression.Conclusions Dapagliflozin can partially repair the decreased expression of SK2 in the myocardium of diabetic rats by inhibiting the NOX/p38MAPK signaling pathway.