中文摘要：

目的：探讨热应激诱导心肌热休克蛋白70（HSP70）mRNA表达上调后,对兔快速心房起搏电重构的影响。方法：将24只新西兰大白兔随机分成热应激＋起搏组（n=8）、起搏组（n=8）和假手术组（n=8）。热应激造模：将新西兰大白兔麻醉后,放入恒温箱中加热,肛温达41℃后持续15 min,再放入室温恢复24 h。起搏：以600次/min行右心房起搏,测量0 h、2 h、4 h、6 h的右房有效不应期（AERP200、AERP150）,AERP频率适应性,心房颤动（AF）诱发率。起搏组对未造模的兔起搏。假手术组只测量不起搏。用逆转录聚合酶链式反应（RT-PCR）检测各组心肌HSP70 mRNA含量。结果：（1）快速心房起搏后,起搏组AERP200和AERP150立即缩短,起搏2h接近最小值[AERP200（79.38±6.23）ms,AERP150（71.25±6.94）ms],较起搏前[AERP200（100.00±6.55）ms,AERP150（89.38±6.78）ms]显著缩短（P〈0.01）;热应激＋起搏组起搏前后AERP无显著变化;（2）0 h时,起搏组右心房处（AERP200-AERP150）/50 ms为（0.21±0.10）ms,起搏2 h、4 h、6 h后分别为（0.16±0.07）、（0.14±0.05）、（0.13±0.05）ms,较起搏前非常显著缩短（P〈0.001）;（3）快速心房起搏前,予以程序性刺激和猝发刺激,各组AF诱发率均为0,起搏后2 h、4 h、6 h AF诱发率：起搏组分别为50.0%、75.0%、87.5%;热应激＋起搏组分别为25.0%、25.0%、37.5%;较起搏组显著减少（P〈0.05）;（4）热应激＋起搏组心脏各部位HSP70 mRNA表达较起搏组和假手术组明显增高（P〈0.05）,起搏组和假手术组间无显著差异。结论：心脏热休克蛋白70 mRNA表达上调后可抑制右心房快速起搏引起的心房电重构。

英文摘要：

Objective：Effects of upregulated expression of heat shock protein 70（HSP70） mRNA induced by heat stress on electrical remodeling induced by rapid atrial pacing in rabbits.Methods：A total of 24 New Zealand rabbits were randomly divided into heat stress＋pacing group（n=8）,pacing group（n=8） and sham operation group（no pacing,n=8）.Model construction by heat stress：New Zealand rabbits after anesthetization were put into heated incubators.When rectal temperature reached 41 ℃,keep it for 15 min,then removed the rabbits to room temperature for a 24h recovery.After right atrial pacing at 600 times/min,measure right atrial effective refractory period（AERP200,AERP150）,frequency adaption of AERP and inducible ratio of atrial fibrillation（AF） at 0h,2h,4h and 6h.In pacing group,rabbits without model construction received pacing.Sham operation groups received measurements without pacing.Reverse transcription-polymerase chain reaction（RT-PCR） was used to measure concentrations of HSP70 mRNA in myocardium of each group.Results：（1） After rapid atrial pacing,AERP200 and AERP150 of pacing group were instantly shorten and neared minimum value at 2h [AERP200（79.38±6.23）ms,AERP150（71.25±6.94）ms].They were significantly decreased compared with those of before pacing [AERP200（100.00±6.55）ms,AERP150（89.38±6.78）ms,P0.01].There were no significant changes of AERP before and after pacing in heat stress ＋ pacing group.（2） At 0 h,the（AERP200 AERP150）/50 ms was（0.21±0.10）ms in right atrium of pacing group and it′s（0.16±0.07）,（0.14±0.05）,（0.13±0.05）ms at 2h,4h,6h respectively,significantly higher than before pacing（0 h,P0.001）.（3） Before rapid atrial pacing,when procedural or burst stimulation was given,inducible ratio of AF was 0 in all groups;the inducible ratio of AF at 2h,4h and 6h after pacing,in pacing group was 50.0%,75.0%,87.5% respectively,they were more than those（25.0%,25.0%,37.5% respectively）of heat stress ＋ pacing group,P0.0