RESUMO
Objective To investigate the role of TLR4/NF-κB signaling pathway under the action of TAK-242 in the cardiomyocyte apoptosis after coronary micro-embolism (CME) in rats.Methods Fortyfive rats were randomized (random number) into three groups:sham operation,CME and CME plus TAK242 groups (n =15 per group).CME was induced by injecting polyethylene microspheres (42 μm) into the left ventricle except the sham group.CME plus TAK-242 group was treated with TAK-242 (2 mg/kg) via the tail vein of mice 30 min before CME modeling.Cardiac function was evaluated 6 h after operation.Tissue biopsy was stained with HBFP to measure the size of infarction area.TUNEL assay was used to detect cardiomyocyte apoptosis.Western blot and qPCR were used to evaluate the protein levels and mRNA expressions of TLR4,NF-κB p65 and cleaved caspase-3,respectively.Statistical analysis was performed using one-way analysis of variance followed by LSD-t test.Results Compared with the sham group,left ventricular ejection fraction (LVEF) in the CME group was significantly decreased [(68.91 ± 4.12) ％ vs.(84.80 ± 2.51) ％,P ＜ 0.05],and the infarction area (P ＜ 0.05),the apoptosis index [(3.36 ± 0.63) ％ vs.(0.19 ± 0.08) ％,P ＜0.05],the mRNA expressions of TLR4,NF-κB p65 and cleaved caspase-3 in CME group were increased significantly (all P ＜ 0.05).Compared with CME group,LVEF in the CME plus TAK-242 group was significantly improved [(75.58 ± 5.01) ％ vs.(68.91 ± 4.12) ％,P＜0.05],and the infarction area [(8.58 ± 2.12) ％ vs.(14.65 ± 4.23) ％,P＜0.05],the apoptosis index [(1.43 ± 0.51) ％ vs.(3.36 ± 0.63) ％,P ＜ 0.05],the mRNA expressions of TLR4,NF-κB p65 and cleaved caspase-3 in CME + TAK-242 group were decreased significantly (all P ＜ 0.05).Conclusions TAK-242 effectively improved CME-induced cardiac dysfunction by regulating TLR4/NF-κB signaling pathway and then reducing the cardiomyocyte apoptosis.