Tu Rong-Hui, Wang Dong-Xiao, Zhong Guo-Qiang, Meng Jian-Jun, Wen Hong, Bi Qi, He Yan
Department of Geriatric Cardiology, First Affiliated Hospital, Guangxi Medical University, 6 Shuangyong Road, Nanning, 530021, Guangxi, China.
Guangxi Key Laboratory of Precision Medicine in Cardio-Cerebrovascular Diseases Control and Prevention, First Affiliated Hospital, Guangxi Medical University, Nanning, 530021, Guangxi, China.
Open Med (Wars). 2021 Oct 18;16(1):1552-1563. doi: 10.1515/med-2021-0340. eCollection 2021.
Activation of the complement component 5a (C5a) and nuclear factor κB (NF-κB) signaling is an important feature of myocardial ischemia/reperfusion (I/R) injury and recent studies show that morphine postconditioning (MP) attenuates the myocardial injury. However, the mediating cardioprotective mechanisms remain unclear. The present study explores the role and interaction of heat shock protein 90 (HSP90), Akt, C5a, and NF-κB in MP-induced cardioprotection.
Male Sprague Dawley rats ( = 160) were randomized into eight groups ( = 20 per group). Rats in the sham group underwent thoracotomy, passing the ligature through the heart but without tying it (150 min), and the other seven groups were subjected to 30 min of anterior descending coronary artery occlusion followed by 2 h of reperfusion and the following treatments: I/R (30 min of ischemia and followed by 2 h of reperfusion); ischemic postconditioning (IPostC, 30 s of ischemia altered with 30 s of reperfusion, repeated for three cycles, and followed by reperfusion for 2 h); MP (0.3 mg/kg morphine administration 10 min before reperfusion); MP combined with the HSP90 inhibitor geldanamycin (GA, 1 mg/kg); MP combined with the Akt inhibitor GSK-690693 (GSK, 20 mg/kg); and MP combined with the C5a inhibitor PMX205 (PMX, 1 mg/kg/day, administration via drinking water for 28 days) and MP combined with the NF-κB inhibitor EVP4593 (QNZ, 1 mg/kg). All inhibitors were administered 10 min before morphine and followed by 2 h reperfusion.
MP significantly reduced the I/R-induced infarct size, the apoptosis, and the release of cardiac troponin I, lactate dehydrogenase (LDH), and creatine kinase-MB. These beneficial effects were accompanied by increased expression of HSP90 and p-Akt, and decreased expression of C5a, NF-κB, tumor necrosis factor α, interleukin-1β, and intercellular cell adhesion molecule 1. However, HSP90 inhibitor GA or Akt inhibitor GSK increased the expression of C5a and NF-κB and prevented MP-induced cardioprotection. Furthermore, GA inhibited the MP-induced upregulation of p-Akt, while GSK did not affect HSP90, indicating that p-Akt acts downstream of HSP90 in MP-induced cardioprotection. In addition, C5a inhibitor PMX enhanced the MP-induced downregulation of NF-κB, while NF-κB inhibitor QNZ had no effect on C5a, indicating that the C5a/NF-κB signaling pathway is involved in MP-induced cardioprotection.
HSP90 is critical for MP-mediated cardioprotection possibly by promoting the phosphorylation of Akt and inhibiting the activation of C5a and NF-κB signaling and the subsequent myocardial inflammation, ultimately attenuating the infarct size and cardiomyocyte apoptosis.
补体成分5a（C5a）和核因子κB（NF-κB）信号通路的激活是心肌缺血/再灌注（I/R）损伤的一个重要特征，最近的研究表明吗啡后处理（MP）可减轻心肌损伤。然而，其介导的心脏保护机制仍不清楚。本研究探讨热休克蛋白90（HSP90）、Akt、C5a和NF-κB在MP诱导的心脏保护中的作用及相互作用。
雄性Sprague Dawley大鼠（n = 160）随机分为八组（每组n = 20）。假手术组大鼠开胸，将结扎线穿过心脏但不结扎（150分钟），其他七组大鼠进行30分钟的冠状动脉前降支结扎，随后再灌注2小时，并给予以下处理：I/R（缺血30分钟，随后再灌注2小时）；缺血后处理（IPostC，30秒缺血与30秒再灌注交替，重复三个周期，随后再灌注2小时）；MP（再灌注前10分钟给予0.3mg/kg吗啡）；MP联合HSP90抑制剂格尔德霉素（GA，1mg/kg）；MP联合Akt抑制剂GSK-690693（GSK，20mg/kg）；MP联合C5a抑制剂PMX205（PMX，1mg/kg/天，通过饮水给药28天）以及MP联合NF-κB抑制剂EVP4593（QNZ，1mg/kg）。所有抑制剂均在吗啡给药前10分钟给予，随后再灌注2小时。
MP显著减小了I/R诱导的梗死面积、细胞凋亡以及心肌肌钙蛋白I、乳酸脱氢酶（LDH）和肌酸激酶同工酶MB的释放。这些有益作用伴随着HSP90和p-Akt表达的增加，以及C5a、NF-κB、肿瘤坏死因子α、白细胞介素-1β和细胞间黏附分子1表达的降低。然而，HSP90抑制剂GA或Akt抑制剂GSK增加了C5a和NF-κB的表达，并阻止了MP诱导的心脏保护作用。此外，GA抑制了MP诱导的p-Akt上调，而GSK不影响HSP90，表明在MP诱导的心脏保护中p-Akt作用于HSP90的下游。此外，C5a抑制剂PMX增强了MP诱导的NF-κB下调，而NF-κB抑制剂QNZ对C5a没有影响，表明C5a/NF-κB信号通路参与了MP诱导的心脏保护。
HSP90对MP介导的心脏保护至关重要，可能是通过促进Akt的磷酸化并抑制C5a和NF-κB信号通路的激活以及随后的心肌炎症，最终减小梗死面积和心肌细胞凋亡。
