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Penehyclidine hydrochloride protects against anoxia/reoxygenation injury in cardiomyocytes through ATP‐sensitive potassium channels, and the Akt/GSK‐3β and Akt/mTOR signaling pathways

Penehyclidine hydrochloride (PHC) can protect against myocardial ischemia/reperfusion (I/R) injury. However, the possible mechanisms of PHC in anoxia/reoxygenation (A/R)‐induced injury in H9c2 cells remain unclear. In the present study, H9c2 cells were pretreated with PI3K/Akt inhibitor LY294002, ATP‐sensitive K+ (KATP) channel blocker 5‐hydroxydecanoate (5‐HD), PHC, or KATP channel opener diazoxide (DZ) before subjecting to A/R injury. Cell viability and cell apoptosis were determined by cell counting kit‐8 assay and annexin V/PI assay, respectively. Myocardial injury was evaluated by measuring creatine kinase (CK) and lactate dehydrogenase (LDH) activities. Intracellular Ca2+ levels, reactive oxygen species (ROS) generation, mitochondrial membrane potential (ΔΨm), and mitochondrial permeability transition pore (mPTP) were measured. The levels of cytoplasmic/mitochondrial cytochrome c (Cyt‐C), Bax, Bcl‐2, cleaved caspase‐3, KATP channel subunits (Kir6.2 and SUR2A), and the members of the Akt/GSK‐3β and Akt/mTOR signaling pathways were determined by western blotting. We found that PHC preconditioning alleviated A/R‐induced cell injury by increasing cell viability, reducing CK and LDH activities, and inhibiting cell apoptosis. In addition, PHC preconditioning ameliorated intracellular Ca2+ overload and ROS production, accompanied by inhibition of both mPTP opening and Cyt‐C release into cytoplasm, and maintenance of ΔΨm. Moreover, PHC preconditioning activated mitochondrial KATP channels, and modulated the Akt/GSK‐3β and Akt/mTOR signaling pathways. Similar effects were observed upon treatment with DZ. Pretreatment with LY294002 or 5‐HD blocked the beneficial effects of PHC. These results suggest that the protective effects of PHC preconditioning on A/R injury may be related to mitochondrial KATP channels, as well as the Akt/GSK‐3β and Akt/mTOR signaling pathways.