Effect of p62-Keap1-Nrf2 signaling pathway on reducing myocardial injury after cardiopulmonary resuscitation in NOD/SCID mice
Xie Tu-xiu;Lyu Jing-jun;Wei Jie;Ye Lu;Department of Emergency,Renmin Hospital of Wuhan University;
Objective To explore the effect of p62-Keap1-Nrf2 antioxidant signaling pathway on reducing myocardial injury after cardiopulmonary resuscitation(CPR) in severe combined immunodeficient mice.Methods A potassium chloride-induced cardiac arrest model was established in healthy male C57 BL/6 mice and non-obese diabetic/severe combined immunodeflcient(NOD/SCID) mice.Eighty male C57 BL/6 mice and Eighty male NOD/SCID mice were randomly divided into five groups,namely control group,2 h after CPR group,12 h after CPR group,24 h after CPR group,and 48 h after CPR group.The return of spontaneous circulation(ROSC) rate,the return of spontaneous respiration(ROSR) rate,and the survival rate of each kind of mice were observed.Western Blot analysis was employed to detect the levels of protein of p62,phospho-p62(Ser351),Keapl and nuclear Nrf2 in ventricular myocytes of each group.Mitochondrial morphology at different time points after CPR was observed by transmission electron microscopy.Results①There was no significant difference in the rate of ROSC and ROSR after CPR between NOD/SCID mice and C57 BL/6 mice(P0.05),but the survival rate of NOD/SCID mice at 48 h post-CPR was significantly lower than that of C57 BL/6 mice(P 0.05).②Compared with the control group,the protein levels of p62 and P-p62(Ser351) in ventricular myocytes of C57 BL/6 mice were decreased at 2 h post-CPR(P 0.01),and then increased at 12 h post-CPR(P 0.01),whereas both of them showed rising trend at all given intervals after CPR(P 0.01).What is more,it was significantly increased in NOD/SCID mice at 2 h,24 h,and 48 h post-CPR compared with that of C57 BL/6 mice(P 0.01).Compared with the control group,the protein levels of Keap1 and nuclear Nrf2 in ventricular myocytes were significantly increased in C57 BL/6 mice and NOD/SCID mice at all given intervals after CPR.In addition,compared with C57 BL/6 mice,the protein levels of Keapl in NOD/SCID mice were significantly increased at all given intervals after CPR,the nuclear Nrf2 protein in ventricular myocytes of NOD/SCID mice showed significantly higher expression at 2 h,12 h,48 h post-CPR,and the difference was statistically significant(P0.01)③There were swollen mitochondria and a large number of autophagosomes in myocardial tissue of C57 BL/6 mice at 2 h post-CPR and 12 h post-CPR.It was also observed that mitochondria were significantly swollen in NOD/SCID mice at 2 h post-CPR and 12 h post-CPR,but there was less autophagosome formation occurred 24 h after CPR and 48 h after CPR.Conclusion Due to the defects of mitophagy,NOD/SCID mice do not initiate mitochondrial autophagy in the early stage of myocardial I/R injury after CPR.p62-Keapl-Nrf2 anti-oxidation signaling pathway plays a cardinal role in reducing myocardial ischemia-reperfusion(I/R) injury after CPR.
【Fund】： 國家自然科學基金(81372020);; 武漢大學人民醫院引導基金(RMYD2018Z15)
【CateGory Index】： R459.7
【CateGory Index】： R459.7