尾加压素Ⅱ诱导培养心肌细胞肥大及对p-p38表达的影响

Induction of cardiomyocyte hypertrophy by urotensin Ⅱ and effects of urotensin Ⅱ on p-p38

目的:观察尾加压素Ⅱ(urotensinⅡ,UⅡ)诱导体外培养的乳鼠心肌细胞肥大及对p-p38表达的影响。方法:培养1d龄乳鼠心肌细胞,用相差显微镜计数心肌细胞搏动频率,细胞图像分析系统测量细胞体积,考马斯亮蓝法测定心肌细胞蛋白含量,[3H]-亮氨酸掺入法测定蛋白合成速率作为心肌肥大指标;免疫沉淀法并p38试剂盒测定p38活性,Western-blot测定p-p38表达。结果:与对照组相比,UⅡ能显著提高心肌细胞搏动频率、细胞体积、心肌细胞蛋白含量、蛋白合成速率,同时显著提高p38活性和p-p38表达。结论:UⅡ可以诱导离体培养的乳鼠心肌细胞肥大,机制与促进p38活性、上调p-p38表达有关。

Objective To observe the inductive effect of urotensin Ⅱ （U Ⅱ ） on cardiomyocyte hypertrophy and the role of U Ⅱ in phosphorylated p38（p-p38） expression. Methods The cardiomyocy＇tes of neonatal rats aged one day were cultured. The pulsation rate of the cardiomyocyte was then measured under the phase contrast microscope. Cell size was determined by the cell image analyzer. The protein content of the cardiomyocyte was detected by coomassie brilliant blue. Protein synthesis rate of the cells was measured by[3H]-leucine incorporation, p38 activity was measured by immuno- precipitation and p38 reagent, p-p38 expression was assessed by Western blot. Results U Ⅱ markedly enhanced the pulsation rate, cell size, protein content, protein synthesis rate and p-p38 expression, and upregulated p38 activity. Conclusion U Ⅱ can induce hypertrophy in the cardiomyocytes of neonatal rat cultured in vitro, whose mechanism may be associated with enhancing the p-p38 activity and expression.