The Role And Mechanism Of TRPA1 Receptor In The Protection Of Myocardial Ischemia-reperfusion Injury By Remote Preconditioning Of Trauma

Objective: To investigate the role of TRPA1 receptor in the protection of myocardial ischemia-reperfusion injury by remote preconditioning of trauma and its related mechanism.Method: Healthy male SD rats with body weight of 250-300 g were divided into five groups(n=18)according to random number table: Sham group(Sham),model group(IR),remote trauma preconditioning group(RPCT),TRPA1 inhibitor + remote trauma preconditioning group(TCS + RPCT)and TRPA1 inhibitor group(TCS).Myocardial ischemia-reperfusion model was established by ligating the left anterior descending(LAD)of rat coronary artery.The LAD in Sham group was only threaded without ligation.In the IR group,LAD was ligated for 30 min and reperfusion for 2h.In RPCT+IR group,abdominal incision was made 15 minutes before ischemia,and then IR model was established.TCS+IR group and TCS+RPCT group were given 1mg/kg TCS via internal jugular vein 25 minutes before ischemia,and other treatments were the same as IR group or RPCT+IR group.Retrograde carotid intubation.Heart rate and blood pressure monitored throughout.After reperfusion,the hearts of rats were taken,and the mass of infarct area(IS),ischemia-risk area(AAR)and left ventricle(LV)were measured by triphenyltetrazole chloride(TTC)staining,and the IS/AAR ratio was calculated.TUNEL staining was used to detect myocardial cell apoptosis index.MDA and SOD levels and ALDH2 activity in myocardial tissue were determined by the kit.The protein expressions of TRPA1,ALDH2 and 4-HNE were detected by Western blot.The expression of TRPA1 in myocardial tissue was observed by immunofluorescence.Results: 1.Evaluation of myocardial ischemia-reperfusion injury model in rats Compared with Sham group,hemodynamic indexes,myocardial infarction volume and myocardial cell apoptosis index were decreased in IR group,MDA level and 4-HNE content of oxidative stress index were increased,while SOD level was decreased(P(27)0.05),indicating that IR injury model of rat myocardium was successfully established.2.Remote preconditioning of trauma alleviates myocardial ischemia-reperfusion injury in rats Compared with IR group,the hemodynamic indexes,IS/AAR ratio and myocardial cell apoptosis index were increased in RPCT group,oxidative stress index MDA level and 4-HNE content were decreased,SOD level and ALDH2 activity were increased,and protein expressions of TRPA1 and ALDH2 in myocardial tissue were increased(P(27)0.05).The results indicated that RPCT alleviated myocardial ischemia-reperfusion injury in rats with the expression of TRPA1 receptor and ALDH2 protein.3.TRPA1 inhibitor TCS blocked the myocardial protective effect of distal trauma preconditioning Compared with IR group,TCS+RPCT group and TCS group had no statistically significant differences in each detection index(P(29)0.05).Compared with RPCT group,myocardial infarction volume and myocardial cell apoptosis index were increased,oxidative stress indexes MDA level and 4-HNE content were increased,SOD level and ALDH2 activity were decreased,and protein expressions of TRPA1 and ALDH2 were decreased in TCS+RPCT group(P(27)0.05).This suggests that TRPA1 receptor mediates the myocardial protective effect of RPCT,and the mechanism is related to the up-regulation of ALDH2 protein expression.Conclusion Remote preconditioning of trauma can alleviate myocardial ischemia-reperfusion injury in rats,and its mechanism is related to activating TRPA1 receptor and regulating ALDH2 activity,thereby alleviating apoptosis and oxidative stress injury.