热休克蛋白70上调对兔快速心房起搏心肌Ca_v1.2,α1c的影响

Influence of upregulation of heat shock protein 70 on Ca_v1.2,α1c induced by rapid atrial pacing in rabbits

目的观察热应激诱导心肌热休克蛋白70(heat shock protein 70,HSP70)表达上调对兔快速心房起搏心肌Ca_v1.2,α1c的影响。方法 24只新西兰大白兔随机分为热应激起搏组、起搏组和假手术组,每组各8只。热应激起搏组先给予热应激,再以600次/min行右心房起搏6h,起搏组以600次/min行右心房起搏6h,假手术组仅植入电极不起搏。采用反转录-PCR检测各组心肌HSP70mRNA、Ca_v1.2,α1cmRNA表达水平,采用免疫组织化学法检测各组心肌HSP70和Ca_v1.2,α1c蛋白表达水平。结果热应激起搏组左心房、右心房、左心耳、右心耳HSP70 mRNA(1.37±0.26、1.35±0.30、1.28±0.21、1.31±0.24)和HSP70蛋白(69.75±3.45、69.00±2.93、68.63±3.23、68.75±2.82)表达水平较起搏组(HSP70mRNA为0.63±0.08、0.64±0.06、0.61±0.09、0.62±0.07,HSP70蛋白为39.75±2.82、37.00±3.85、39.00±3.89、38.38±2.92)和假手术组(HSP70mRNA为0.59±0.10、0.54±0.09、0.57±0.10、0.54±0.13,HSP70蛋白为39.00±3.21、38.38±3.74、37.75±3.28、39.00±4.00)明显增高(P<0.01),起搏组与假手术组比较差异无统计学意义(P>0.05);起搏组左心房、右心房、左心耳、右心耳Ca_v1.2,α1cmRNA(0.51±0.15、0.50±0.09、0.53±0.09、0.53±0.10)和Ca_v1.2,α1c蛋白(21.88±2.36、21.75±2.49、21.50±2.45、21.38±2.33)表达水平较热应激起搏组(Ca_v1.2,α1cmRNA为0.66±0.06、0.68±0.05、0.68±0.05、0.64±0.38,Ca_v1.2,α1c蛋白为26.00±2.73、25.25±1.83、25.13±2.03、25.38±2.00)和假手术组(Ca_v1.2,α1cmRNA为0.64±0.10、0.66±0.10、0.67±0.04、0.63±0.03,Ca_v1.2,α1c蛋白为26.75±3.37、26.63±1.85、26.50±3.07、26.13±3.91)明显降低(P<0.01),热应激起搏组与假手术组比较差异无统计学意义(P>0.05)。结论心肌HSP70表达上调后可抑制快速心房起搏心肌Ca_v1.2,α1c的重构。

Objective To investigate the influence of upregulation of heat shock protein 70(HSP 70)due to heat stress on Ca_v1.2,α1cinduced by rapid atrial pacing in rabbits.Methods Twenty-four New Zealand rabbits were randomly divided into heat stress+ pacing group,pacing group and sham operation group,with 8rabbits in each group.The right atrium(RA)was paced at 600beat/min for 6hin heat stress+ pacing group after heat strees and in pacing group,and sham operation group received no pacing.The expressions of HSP70 and Ca_v1.2,α1cmRNA and proteins were detected by RT-PCR and immunohistochemistry.Results The levels of HSP70mRNA(1.37±0.26,1.35±0.30,1.28±0.21,1.31±0.24)and protein(69.75±3.45,69.00±2.93,68.63±3.23,68.75±2.82)of left atrium(LA),RA,left atrial appendage(LAA)and right atrial appendage(RAA)in heat stress+ pacing group were significantly higher than those in pacing group(HSP70mRNA:0.63±0.08,0.64±0.06,0.61±0.09,0.62±0.07;HSP70protein:39.75±2.82,37.00±3.85,39.00±3.89,38.38±2.92)and sham operation group(HSP70 mRNA:0.59±0.10,0.54±0.09,0.57±0.10,0.54±0.13;HSP70protein:39.00±3.21,38.38±3.74,37.75±3.28,39.00±4.00)(P<0.01),and there were no significant differences between pacing group and sham operation group(P>0.05).The levels of Ca_v1.2,α1cmRNA(0.51±0.15,0.50±0.09,0.53±0.09,0.53±0.10)and protein(21.88±2.36,21.75±2.49,21.50±2.45,21.38±2.33)of LA,RA,LAA and RAA in pacing group were significantly lower than those in heat stress+ pacing group(Ca_v1.2,α1cmRNA:0.66±0.06,0.68±0.05,0.68±0.05,0.64±0.38;Ca_v1.2,α1cprotein:26.00±2.73,25.25±1.83,25.13±2.03,25.38±2.00)and sham operation group(Ca_v1.2,α1cmRNA:0.64±0.10,0.66±0.10,0.67±0.04,0.63±0.03;Ca_v1.2,α1cprotein:26.75±3.37,26.63±1.85,26.50±3.07,26.13±3.91)(P<0.01),and there were no significant differences between heat stress+ pacing group and sham operation group(P>0.05).Conclusion The upregulated HSP70 can inhibit the myocardial remodeling of Ca_v1.2,α1cinduced by rapid atrial pacing in rabbits.