阿托伐他汀通过上调大电导钙敏感钾通道电流影响大鼠主动脉平滑肌细胞膜电位研究

Influence of atorvastatin on membrane potential of rat aortic smooth muscle cells through up-regulating current of large conductance calcium-sensitive potassium channel

目的探讨阿托伐他汀通过上调大电导钙敏感钾通道(BKca)电流影响大鼠主动脉平滑肌细胞(ASMCs)膜电位机制。方法浓度分组:生理盐水对照组、阿托伐他汀浓度分别为10、25、50、100、150μmol/L细胞共培养组。应用+/-BKca通道阻断剂iberiotoxin(IBTX,100 nmol/L)时通过激光共聚焦显微镜检测ASMCs膜电位;全细胞膜片钳技术检测ASMCs全细胞钾电流密度(pA/pF)。结果ASMCs与阿托伐他汀共培养后细胞膜电位荧光值下降,呈阿托伐他汀浓度依赖性;与对照组比较,100μmol/L及150μmol/L阿托伐他汀组荧光值下降,有统计学意义(P<0.05)。对照组中加入IBTX明显降低pA/pF值(P<0.05);与对照组比较,阿托伐他汀共培养组pA/pF值增加,有统计学意义(P<0.05);而100μmol/L阿托伐他汀+IBTX组电流密度变化无统计学意义(P>0.05)。与100μmol/L阿托伐他汀组比较,100μmol/L阿托伐他汀+IBTX组pA/pF值减小,有统计学意义(P<0.05)。结论阿托伐他汀上调BKca通道电流导致ASMCs超极化,进而影响血管平滑肌细胞生物学活性。

Objective To investigate the influencing mechanism of atorvastatin(ATV)on membrane potential of rat aortic smooth muscle cells(ASMC)through up-regulating current of large conductance calcium-sensitive potassium channel(BKca).Methods ASMC were divided into control group(normal saline),10μmol/L ATV group,25μmol/L ATV group,50μmol/L ATV group,100μmol/L ATV group and 150μmol/L group.When BKca blocker-iberiotoxin(IBTX,100 nmol/L)was used,ASMC membrane potential was detected by using laser scanning confocal microscope(LSCM).The potassium current density(pA/pF)of the whole ASMC was detected by using whole-cell patch clamp technique.Results The fluorescence value of ASMC membrane potential decreased in a concentration-dependent manner after the co-cultivation of ASMC and ATV.Compared with control group,the fluorescence value decreased in 100μmol/L ATV group and 150μmol/L group(P<0.05).IBTX reduced significantly pA/pF value in control group(P<0.05).Compared with control group,the increases of pA/pF value had statistical significance in all ATV groups(P<0.05).The changes of potassium current density had no statistical significance in 100μmol/L ATV+IBTX group(P>0.05).Compared with 100μmol/L ATV group,the decrease of pA/pF value had statistical significance in 100μmol/L ATV+IBTX group(P<0.05).Conclusion ATV can induce the hyperpolarization of ASMC through up-regulating the current of BKca,and then influences the biological activity of ASMC.