Experimental Study Of The Mechanisms Of Soluble Epoxide Hydrolase Inhibitor Attenuating Arrythmias

Background:Ischemic arrhythmias is one of the most common reasons for patients dying. As was reported before, the new soluble epoxide hydrolase inhibitor, t-AUCB (trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid) was good for ischemic arrhythmias, but its mechanisms still remain unknown. MicroRNA-1(miR-1) was found to inhibit the expression of KCNJ2, GJA1, connexin43(Cx43) and the subunit of potassium channel, Kir2.1thus result in fatal arrhythmias. What’s more, in our previous studies, it’s demonstrated that t-AUCB can block the expression of miR-1in the ischemic region in the heart. So we speculate that t-AUCB may attenuate ischemic arrhythmias through the modulation of the expression of miR-1and its target genes KCNJ2, GJA1mRNA and its encoded protein Kir2.1, Cx43.Objective:To explore the mechanisms for t-AUCB inhibiting ischemic arrhythmias, and its relationship with miR-1, KCNJ2, GJA1mRNA, Kir2.1and Cx43.protein.Methods:The Kungming male mice of8weeks old were administered with t-AUCB of different concentraions (0.2,1,5mg/L) or drinking water for7days. After then, they were operated the myocardial infartion or sham surgery.24hours later, the mice were put to death and their hearts were taken out for next experiments. In the transfection experiment, the Kunming male mice were administered with5mg/L t-AUCB for7days, and after the surgery, they were tale-injected with the transfective agent micrONTM mmu-miR-la-3p agomir or micrONTM mmu-miR-1a-3p agomir-negative control for control. The pathology of hearts were detected with HE (hematoxylin-eosin) staining. mir-1, KCNJ2, GJA1mRNA expression were determined by Real-time PCR. Kir2.1, Cx43protein expression were quantified by Western-blotting.Results:1. The miR-1level in the ischemic region of mice hearts in drinking water plus MI group was significantly higher than that in drinking water plus sham group, whereas KCNJ2, GJA1mRNA and Kir2.1, Cx43protein expression were significantly lower (all P<0.05).2. t-AUCB can dose-dependently inhibit the miR-1level and increase the KCNJ2, GJA1mRNA and Kir2.1, Cx43protein expression in the ischemic region of mice hearts (all P<0.05).4. mmu-miR-1a-3p-agomir could elevate the miR-1level, thus down-regulate KCNJ2, GJA1mRNA and Kir2.1, Cx43protein expression in the ischemic zone of mice hearts, and t-AUCB can reverse these effects.(all P<0.05).Conclusions:t-AUCB may inhibit ischemic arrhythmias through inhibiting the expression of miR-1and enhancing the expression of its target gene KCNJ2, GJA1, its target protein Kir2.1, Cx43.