κ-阿片肽受体激活抑制内皮素-1诱导的心肌细胞肥大与细胞外信号调节激酶通路有关

Inhibition of activatedκ-opioid receptor to myocardical hypertrophy induced by ET-1 in neonatal rats by extracellular signal-regulated kinase pathway

目的讨论κ-阿片肽受体(kappa-opioid receptor,κ-OR)激活后通过细胞外信号调节激酶通路对内皮素-1(vascular endothelin-1,ET-1)诱导的心肌细胞肥大的抑制作用。方法体外原代培养大鼠乳鼠心肌细胞,ET-110 nmol·L^(-1)诱导心肌细胞肥大,观察κ-OR激动剂(U50488H)1μmol·L^(-1)对心肌细胞的作用,并探讨细胞外信号调节激酶1/2特异性抑制剂(U0126)1μmol·L^(-1)、蛋白激酶C(PKC)抑制剂Ro-31-8220(50 nmol·L^(-1))、百日咳毒素(pertussis toxin,PTX)5 mg·L^(-1)、κ-OR拮抗剂nor-binaltorphimine(NOR-BNI,1μmol·L^(-1))存在时,κ-OR的激活对心肌细胞肥大的影响及相关机制。心肌细胞的体积应用消化分离法及计算机图像分析系统测定;心肌细胞的心钠素(atrial natriuretic peptide,ANP)的mRNA相对表达利用RT-PCR法测定;心肌细胞ERK1/2的相对表达水平应用Western blot法测定;心肌细胞的形态变化利用相差显微镜观察。结果ET-1可以使心肌细胞体积增大,ANPmRNA表达增多,ERK1/2表达增多;与ET-1(10 nmol·L^(-1))组相比,U50488H(1μmol·L–1)可明显使ET-1诱导的心肌细胞体积变小,ANPmRNA表达减少,ERK1/2表达减少,U0126(1μmol·L^(-1))、Ro-31-8220(50 nmol·L^(-1))与其抑制程度相似,三者差异无显著性;当用U0126(1μmol·L^(-1))、Ro-31-8220(50 nmol·L^(-1))预处理时U50488H(1μmol·L^(-1))的抑制现象部分消失,但当用PTX(5 mg·L^(-1))、NOR-BNI(1μmol·L^(-1))(κ-OR受体拮抗剂)预处理时U50488H(1μmol·L^(-1))的抑制现象基本消失。结论κ-OR激动剂U50488H能抑制内皮素-1诱导的大鼠心肌细胞肥大,其作用机制主要与其能抑制胞外信号调节激酶通路的上游元件PKC的激活有关。

Aim To investigate the inhibitory effect of kappa-opioid receptor(κ-OR)stimulation on extracellular signal-regulated kinase pathway on ET-1-induced cardiomyocyte hypertrophy in vitro cultured myocardial cells from neonatal rats.Methods Myocardial cells of neonatal rats were cultured in vitro.The hypertrophic myocytes were induced by ET-1(10 nmol·L^(-1))beforeκ-OR agonist U50488H(1μmol·L^(-1))was administered.The antihypertrophic effect ofκ-OR stimulation was observed in the presence of U0126(1μmol·L^(-1)),Ro-31-8220(50 nmol·L^(-1))and PTX(5 mg·L^(-1)).The cardiomyocytes volume was measured by computer photographalysis system.The relative expression of ERK1/2 was determined by Western blot.The morphological changes in cardiomyocytes were observed under an inverted phase contrast microscope.The expression of mRNA of atrial natriuretic peptide(ANP)was determined by RT-PCR.Results Compared with normal control group,ET-1 could induced cardiomyocyte hypertrophy.Compared with ET-1 model group,U50488H(1μmol·L^(-1))could obviously inhibit ET-1-induced increase of the cardiomyocytes volume,expression of ANPmRNA and expression of ERK1/2,which was similar to U0126(1μmol·L^(-1))and Ro-31-8220(50 nmol·L^(-1));however,the inhibitory effects of U50488H were partly lost when preincubated with U0126(1μmol·L^(-1))and Ro-31-8220(50 nmol·L^(-1));the inhibitory effects of U50488H,U0126(1μmol·L^(-1))and Ro-31-8220(50 nmol·L^(-1))were lost when preincubated with NOR-BNI.Conclusion The stimulation of kappa-opiod can inhibit myocardial hypertrophy induced by ET-1,which is possibly via attenuating ERK1/2.