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Abstract Objective To investigate the effects of regulation of autophagy on H9c2 cardiomyocytes exposed to hy-poxia/reoxygenation (H/R) injury and its significance. Methods H9c2 cardiomyocyte H /R injury model was estab-lished by hypoxia for 2 hours and reoxygenation for 4 hours. 3- methyladenine (3- MA) was used as autophagy inhibitor, and rapamycin as autophagy inducer. Cultured cardiomyocytes were randomly divided into four groups:sham group, H/R group, H/R+3MA- pre- treated group(100 mol/L 3- MA) and H/R+rapamycin- pre- treated group (100 nmol/L ra-pamycin). cellviability was measured by MTT, autophagic vacuoles by transmission electron microscopic analysis, apop-tosis rate of cardiomyocyte by flow cytometry analysis, and protein expressions of autophagy- related proteins LC3 and Beclin 1, apoptosis- related proteins Bcl- 2, Bax and cleaved Caspase- 9, Caspase- 3 by Western blot. Results H/R strongly upregulated autophagy, induced myocyte apoptosis, and reduced cellviability (P<0.01). Western blot showed that H/R inhibited Bcl- 2 expression, promoted Bax, caspase- 9 and - 3 activation expression (P<0.01). Autophagy in-hibitor 3- MA significantly attenuated H / R- induced injury, inhibited mitochondria mediated apoptosis and downstream protein expression (P<0.01). Autophagy inducer rapamycin exacerbated cellapoptosis via mitochondrial apoptotic path-way(P<0.01). Conclusion Enhanced autophagy plays detrimental role during H9c2 cardiomyocyte H/R injury. Inhibit-ing autophagy with 3- MA may protect against H/R injury through attenuating mitochondria apoptotic pathway.
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