LncRNA 93358 Aggravates the Apoptosis of Myocardial Cells After Ischemia-Reperfusion by Mediating the PI3K/AKT/mTOR Pathway

Abstract

To investigate the impact of LncRNA 93358 on ischemia-reperfusion induced myocardial cell apoptosis and the underlying mechanism. After being subjected to hypoxia for 4 h, three models of hypoxia-reoxygenation (H/R) with reoxygenation times of 8, 16, and 24 h were established. The expression of LncRNA 93358 was detected by qPCR, and the most suitable conditions were selected for subsequent experiments. The LncRNA 93358 knockout rat myocardial cells were established by transfecting with shRNA-93358 and identified by the RT-PCR assay, followed by constructing the in vitro H/R model. H/R myocardial cells were treated with blank medium (Model), shRNA-NC (LncRNA 93358 NC), shRNA-93358 (LncRNA 93358 knock), and shRNA-93358 + LY294002 (LncRNA 93358 knockout+LY294002), respectively. Normal myocardial cells treated with blank medium was taken as the control group. The cell cycle and apoptosis were analyzed by the flow cytometry. The level of cellular SOD and MDA was measured by the ELISA assay. The expression level of LncRNA 93358 was determined by the RT-PCR assay and Western blot assay was utilized to evaluate the expression level of AKT1, p-AKT1, mTOR, p-mTOR, bcl-2, and Bax. Compared to control, the expression of LncRNA 93358 in H9C2 cells was significantly increased under hypoxic conditions for 4 h followed by reoxygenation for 8 h/16 h. Moreover, the expression of LncRNA 93358 was relatively higher under hypoxic conditions for 4 h followed by reoxygenation for 16 h. Compared to control, significantly lower p-mTOR/mTOR and p-AKT1/AKT1 level was observed in the model group, accompanied by the elevated MDA level, declined SOD level, increased apoptotic rate, enhanced arrest at S phase, upregulated Bax, and downregulated Bcl-2. Compared to the model and LncRNA 93358 NC group, the expression level of p-mTOR/mTOR and p-AKT1/AKT1 was significantly promoted in the LncRNA 93358 knock group, accompanied by the declined MDA level, increased SOD level, reduced apoptotic rate, increased arrest at G0/G1 phase, downregulated Bax, and upregulated Bcl-2, which were dramatically reversed in the LncRNA 93358 knockout+LY294002 group. LncRNA 93358 aggravated the apoptosis of myocardial cells after ischemia-reperfusion by mediating the PI3K/AKT/mTOR pathway.