Objective: We demonstrate the protective effects of the siRNA-mediated inhibition of the interleukin-28 receptor alpha (IL28RA) subunit on cardiomyocytes in hypoxia/reoxygenation (H/R) injury and explore the associated mechanism.
Methods: After designing and synthesizing three pairs of siRNA that effectively reduced IL28RA gene expression in vitro (siRNA-6158, siRNA-6160, and siRNA-6162), primary neonatal rat cardiomyocytes were transfected using a liposome transfection method. Six groups were included based on the siRNA that was used and the treatment simulating reperfusion injury: control group, H/R group, H/R+negative control group, H/R+siRNA-6158 group, H/R+siRNA-6160 group, and H/R+siRNA-6162 group. Cell survival and apoptosis rates were measured along with lactate dehydrogenase levels in the cell culture supernatant. Protein levels of IL28RA, phosphatidylinositol 3-kinase, catalytic subunit gamma (PI3KCG), Bcl-2, Bax, and β-actin were also measured.
Results: The H/R+siRNA-6158 and H/R+siRNA-6160 groups had significantly higher survival rates and increased PI3KCG-to-β-actin and Bcl-2-to- Bax ratios than the the H/R and H/R+negative control groups (p<0.05). The H/R+siRNA-6158 and H/R+siRNA-6160 groups also exhibited reduced rates of apoptosis and reduced IL28RA-to-β-actin ratios (p<0.05). No significant difference was observed among the H/R+siRNA-6162, H/R, and H/R+negative control groups.
Conclusion: IL28RA siRNA-6158 and -6160 were able to protect cardiomyocytes from H/R injury by inhibiting apoptosis. This strategy of inhibiting IL28RA gene expression may reduce reperfusion injury in the treatment of patients with acute myocardial infarction.