Poly(
adenosine 5'-
diphosphate ribose)
polymerase (PARP) is a nuclear
enzyme activated by
DNA strand breaks and plays an important role in the tissue injury associated with
ischemia and reperfusion. The aim of the present study was to investigate the protective effect of
5-aminoisoquinolinone (5-AIQ), a
PARP inhibitor, against oxidative stress-induced apoptosis in H9c2 cardiomyocytes.
5-AIQ pretreatment significantly protected against H2O2-induced cell death, as determined by the XTT assay, cell counting,
terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, and Western blot analysis of apoptosis-related
proteins such as
caspase-3, Bax, and Bcl-2. Upregulation of
antioxidant enzymes such as
manganese superoxide dismutase and
catalase accompanied the protective effect of
5-AIQ on H2O2-induced cell death. Our data also showed that
5-AIQ pretreatment protected H9c2 cells from H2O2-induced apoptosis by triggering activation of Akt and
glycogen synthase kinase-3β (GSK-3β), and that the protective effect of
5-AIQ was diminished by the PI3K inhibitor
LY294002 at a concentration that effectively abolished 5-AIQ-induced Akt and GSK-3β activation. In addition, inhibiting the Akt/GSK-3β pathway by
LY294002 significantly attenuated the 5-AIQ-mediated decrease in cleaved
caspase-3 and Bax activation and H9c2 cell apoptosis induction. Taken together, these results demonstrate that
5-AIQ prevents H2O2-induced apoptosis in H9c2 cells by reducing intracellular
reactive oxygen species production, regulating apoptosis-related
proteins, and activating the Akt/GSK-3β pathway.