We examined the protective role of microRNA-30b (miR-30b) in ischemia-reperfusion (I/R)-induced injury in rat H9C2 cardiomyocytes. H9C2 cells were subjected to hypoxia-reoxygenation (H/R) treatment to simulate ischemia-reperfusion (I/R) injury. H9C2 cells were divided into: vehicle control (VC) group; scrambled inhibitors (INC) group; scrambled mimics (MNC) group; H/R+VC group; H/R+INC group; H/R+mimics group. H/R induced apoptosis was detected by flow cytometry and the pathways involved in miR-30b-mediated protection were examined by analyzing the expression of miR-30b, Bcl-2, Bax, Caspase-3, KRAS, p-AKT and total AKT in H9C2 cells. Overexpression of miR-30b mimic (H/R+mimics group) significantly increased Bcl-2 and Bcl-2/Bax levels and decreased Bax and Caspase-3 levels, compared with the H/R+VC group (all P<0.05). Consistent with this, the apoptosis rate was significantly decreased in the H/R+mimics group (P<0.05) compared with the H/R+VC group. Western blot analysis revealed that overexpression of miR-30b mimic resulted in significantly increase in AKT activation and decreased KRAS, compared to the H/R+VC group (both P<0.05). In conclusion, the H/R induced apoptosis decreased miR-30b expression, but over-expression of miR-30b inhibited H/R induced apoptosis. The observed miR-30b-mediated protection against H/R induced apoptosis involved the upregulation of Ras-PI3K-Akt pathway.
Keywords: Cell apoptosis; H9C2 cardiomyocytes; Hypoxia–reoxygenation; Ischemia–reperfusion; MicroRNA-30b; Ras–PI3K–Akt.
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