Attenuating oxygen-glucose deprivation-caused autophagosome accumulation may be involved in sevoflurane postconditioning-induced protection in human neuron-like cells

Application of the commonly used volatile anesthetic sevoflurane after brain ischemia (sevoflurane postconditioning) attenuates ischemic brain injury. It is not known whether autophagy plays a role in this sevoflurane postconditioning-induced neuroprotection. Human SH-SY5Y cells were induced to become neuron-like cells. These cells were subjected to 1 h oxygen-glucose deprivation (OGD) and then exposed to sevoflurane for 1 h. Chloroquine, an inhibitor of autolysosomes, rapamycin, an autophagy inducer, or 3-methyladenine (3-MA), an autophagy inhibitor, were incubated with cells during OGD and sevoflurane exposure. OGD and the subsequent simulated reperfusion increased lactate dehydrogenase (LDH) release from the cells. This increase was dose-dependent inhibited by sevoflurane postconditioning. OGD increased the ratio of microtubule-associated protein 1 light chain 3 (LC3) II to LC3I and the expression of beclin-1 and p62. These increases were attenuated by sevoflurane. Sevoflurane alone did not have any effects on the expression of p62, beclin-1 and the ratio of LC3II to LC3I. Sevoflurane also enhanced the co-location of autophagosomes and lysosomes. Chloroquine increased the ratio of LC3II to LC3I, p62 and LDH release in cells subjected to OGD. Sevoflurane postconditioning attenuated OGD-induced inactivation of Akt and mechanistic target of rapamycin (mTOR). Inducing autophagosome generation by rapamycin attenuated sevoflurane postconditioning-reduced LDH release. Inhibition of autophagosome generation by 3-MA decreased OGD-induced LDH release. These results suggest that OGD increase autophagosome accumulation via increased formation of autophagosomes and reduced autophagosome clearance and that attenuation of OGD-induced autophagosome accumulation may contribute to sevoflurane postconditioning-induced cell protection.