N-acetylcysteine promoted aging through adjusting expression of cell cycle related protein in neonatal SD rat cardiomyocytes / 中华心血管病杂志

ABSTRACT

<p><b>OBJECTIVE</b>To observe the effects of N-acetylcysteine (NAC) on aging in neonatal SD rat cardiomyocytes and explore related mechanisms.</p><p><b>METHODS</b>Cultured cardiomyocytes were randomized assigned to 6 groups 1-day, 5-day, 10-day, 1-day + NAC (1 mmol/L), 5-day + NAC (1 mmol/L) and 10-day + NAC (1 mmol/L). Flow cytometry was used to examine cell cycle. Real-time quantitative PCR and Western blot were used to determine mRNA and protein expression of p16INK4a, p21WAF1 and Rb gene. beta-galactosidase staining kit was used to investigate beta-galactosidase activity.</p><p><b>RESULTS</b>Numbers of cardiomyocytes resided in G(0)/G(1) phase were significantly higher in the group of 5-day + NAC and 10-day + NAC compared with 5-day, 10-day, respectively (P < 0.05). The mRNA and protein expression of p16INK4a and p21WAF1 were also significantly higher in the group of 5-day + NAC and 10-day + NAC compared with 5-day, 10-day, respectively (P < 0.05 or P < 0.01). The mRNA and protein expression of Rb was significantly lower in the group of 5-day + NAC and 10-day + NAC compared with 5-day, 10-day, respectively (P < 0.01). beta-galactosidase activity was not affected by NAC in the 1-day + NAC group but was significantly higher in 5-day + NAC and 10-day + NAC groups compared with the 5-day, 10-day groups (all P < 0.05).</p><p><b>CONCLUSION</b>NAC could promote aging through upregulating the expression of p16INK4a and p21WAF1 and inhibiting Rb phosphorylation in neonatal SD rat cardiomyocytes.</p>