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

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 cardiomyocytes 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.