Urocortin 致大鼠心肌细胞肥大由PKA信号通路介导.doc

Urocortin 致大鼠心肌细胞肥大由PKA信号通路介导
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作者:梁春光,王洪新,刘春娜,刘杰,黄雷
【摘要】目的通过观察PKA拮抗剂H-诱导乳大鼠心肌细胞肥厚的作用,诱导的大鼠心肌细胞肥厚的信号转导机制。方法以体外培养的乳大鼠心肌细胞为模型, μmol·L-1诱导心肌肥大,观察H-89 μmol·L-1和Astressin 1 μmol·L-1的作用, μmol·L-1对心肌肥厚的作用机制。用消化分离法及计算机图像分析系统检测心肌细胞体积;[3H]亮氨酸掺入法测定心肌细胞蛋白的合成;用Western蛋白印迹法测定ANP表达。结果 UCN μmol·L-1使心肌细胞体积、蛋白合成和ANP表达明显增加,H-89 μmol·L-1和Astressin 1 μmol·L-诱导的心肌肥大。结论 Urocortin可能通过CRF-R2并通过PKA信号通路诱导乳大鼠心肌细胞肥大。
【关键词】 Urocortin 心肌肥大 PKA H-89
Abstract: Objective To observe the inhibitive effects and signal transduction by H-89 and CRF receptor antagonist Astressin on hypertrophic myocardial cells induced by UCN in neonatal rats and study the signal transduction mechanism of hypertrophic myocardial rats induced by UCN. Methods Using the myocardial cells of neonatal rats cultured in vitro as models, and inducing myocardial hypertrophy by using UCN μmol·L-1 to observe the effect of H-89 μmol·L-1 and Astressin 1 μmol·L-1 and discuss the mechanism of effect of UCN μmol·L-1 on myocardial hypertrophy. The cardiomyocytes volumes were measured puter photograph analysis system. The protein synthetic rate was obtained through measuring the incorporation of [3H]-leucine into myocyte protein by liquid scintillation method. The expression of ANP was determined by western-blot. Results UCN enhanced the cardiomyocyte volume, the synthesis and the expression of ANP. H-89 μmol·L-1 and Astressin 1 μmol·L-1 can inhibit myocardial cells hypertrophy induced by UCN. Conclusions The hypertrophic effect of UCN in neonatal rats’ cardiomyocytes is mediated via CRF-R2 and activation of the PKA pathway.

Key words:Urocortin; myocardial cells hypertrophy; PKA; H-89
Urocortin(UCN)是在1995年新发现的一个神经肽,在心脏中[1]有表达,是一个很重要的心血管活性肽。UCN可以使新生大鼠心肌细胞ANP和BNP分泌显著增加[2], mRNA在肥大心肌上的表达数量明显比在正常心脏上的表达数量高[3],参与心肌肥大作用。UCN与CRF-R2具有很高亲和力[4,5],能够使心肌细胞内cAMP积聚增加[2]300。大量实验也表明PKA信号通路参与心肌肥厚作用。

诱导心肌肥厚的作用机制,体外诱导心肌肥大基础上,重点观察应用PKA抑制剂H-89和CRF-R拮抗剂Astressin对心肌