Effects Of High Integrin-linked Kinase Expression On Cardiomyocyte Apoptosis Induced By Doxorubicin

Objective To explore the effects of high integrin-linked kinase(ILK) expression on apoptosis induced by doxorubicin(DOX) in cardiomyocytes and to investigate its possible mechanisms.Methods Cultured neonatal rat cardiomyocytes were randomly divided into three groups: control group, GFP+DOX group (adenoviral vector expressing GFP was added to the cultured medium 24 hours before the cardiomyocytes were exposed continuously to DOX) and ILK+DOX group (adenoviral vector expressing ILK was added to the cultured medium 24 hours before the cardiomyocytes were exposed continuously to DOX). The apoptosis rate of myocardial cells was determined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL). Expression of several apoptosis-related genes, including Fas, FasL, Bax and Bcl-2 in cardiomyocytes was examined by fluorescent quantitative real-time PCR. All data were analyzed using SPSS17.0 statistical analysis software.Results1. Compared with control group, the ratio of apoptotic cardiomyocytes in GFP+DOX group was significantly higher than that in control group [ (22.88±7.75)% vs. (4.45±2.12)%, P<0.01],but in ILK+DOX group ,it was lower than that in GFP+DOX group[ (14.23±5.56)% vs. (22.88±7.75)%, P<0.05].2. Compared with control group, the mRNA expression of Fas, FasL and Bax in GFP+DOX group was higher [ Fas: (1.39±0.15) vs. (0.78±0.18), P<0.01; FasL : (0.69±0.25) vs. (0.11±0.02), P<0.01; Bax:(1.84±0.28) vs. (0.98±0.08) , P<0.01],and the mRNA expression of Bcl-2 was lower than that in control group [ (0.14±0.02)vs. (0.98±0.02), P<0.01]. In ILK+DOX group, the mRNA expression of Fas, FasL and Bax was lower than that in GFP+DOX group [ Fas: (1.14±0.12) vs. (1.39±0.15) , P<0.05; FasL:(0.20±0.03) vs. (0.69±0.25) , P<0.05;Bax:(1.29±0.21) vs. (1.84±0.28) , P<0.05] , and the mRNA expression of Bcl-2 was higher [(0.16±0.01) vs. (0.14±0.02), P<0.05].Conclusion Myocardial apoptosis is an important mechanism of doxorubicin-induced cardiomyopathy. Over-expression of ILK inhibits DOX-induced apoptosis in cardiomyocytes, possiblly, mediated through up-regulating the expression of Bcl-2 and inhibiting the expression of Fas, FasL and Bax.