Abstract: Objective To investigate the mechanism of miR-133a in reversing neonatal rat cardiomyocyte hypertrophy induced
by phenylephrine. Methods A miR-133a precursor cDNA was used to construct an adenovirus vector, which was transfected
into 293 cells to harvest miR-133a-containing virus. Neonatal rat cardiac myocytes treated by phenylephrine were exposed to
miR-133a adenovirus, and the changes in cell area was measured; the expression levels of miR-133a and Acta1, Actc1, Actb,
Myh6, Myh7, and BNP mRNAs were detected by quantitative RT-PCR. Results Phenylephrine treatment increased the area of
cardiomyocytes by more than 3 folds and significantly enhanced the expression levels of Acta1, Actc1, Actb, Myh6, Myh7 and
BNP mRNAs. All these changes were obviously reverse by miR-133a treatment. Conclusion miR-133a is an important
regulator of phenylephrine-induced cardiomyocyte hypertrophy and negatively regulates this process