ABSTRACT
Aim To observe the mRNA expressions of cell cycle regulators at different time points during the hypertrophic process of H9 c2 rat cardiomyoctes in-duced by angiotensin Ⅱ stimulation.Methods H9c2 myocytes were stimulated with 1.0 μmol · L-1 angio-tensin Ⅱ (Ang Ⅱ)for scheduled time.Cells were stained by Rhodamine labeled phalloidin and the cell area was measured by ImageJ software.mRNA expres-sion levels of cyclin B,D,E,cyclin dependent kinase (CDK)1,2,4,6,and CDK inhibitor p21 were de-termined by real-time PCR at different time points (0, 5,10,30 min,and 1,2,3,6,12,24,48 h).Re-sults H9 c2 cell size increased soon after stimulation of Ang Ⅱ;mRNA expressions of cyclin E,CDK4 and CDK2 all reached the peak at 5 min after stimulation of Ang Ⅱ;mRNA expression of cyclin D was increased dramatically at 10 min,followed by a decrease trend. However,the mRNA expression of cyclin B and CDK6 both showed two peaks,a p2 1 mRNA level was up to the peak at 30 min,and the expression was lowest at 3h.Although its expression increased gradually after 3h,p21 mRNA remained low level.Conclusion mRNA expression levels of the cell cycle regulators fluctuate and jointly facilitate the hypertrophic process of cardiomyocytes.