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Autophagy is usually up-regulated to provide more ATP in response to starvation or OGD (oxygen-glucose deprivation), but the relationship between autophagy and ATP, [Ca2+]i (intracellular free Ca2+ concentration) or MMP (mitochondrial membrane potential) during reoxygenation is not yet fully clear. The role of autophagy is unknown in PC12 cells subjected to 2 h OGD with different time points of reoxygenation. In the present study, we showed that Beclin-1 was up-regulated beginning at 0 h reoxygenation peaking at 24 h and lasting for 48 h. Cell viability was decreased from 0 to 48 h reoxygenation, reaching its minimum at 10 h reoxygenation. ATP was decreased from 0 to 10 h reoxygenation, reaching its minimum at 4 h reoxygenation. A significant negative correlation was observed between ATP and Beclin-1 ( r = −0.61, P<0.05) at 0 h reoxygenation, but ATP was not significant related ( r = 0.24, P>0.05) to Beclin-1 at 24 h reoxygenation. Besides, Nimodipine, a calcium antagonist, significantly reduced [Ca2+]i and Beclin-1, but increased MMP in OGD/R-treated cells. At 24 h reoxygenation, Beclin-1 expression reached its maximum, cell viability continued to increase, and ATP was higher than that before OGD. These results suggest that energy metabolism dysfunction can induce autophagy during OGD in PC12 cells. Increased [Ca2+]i and decreased MMP may induce autophagy during reoxygenation in PC12 cells. Autophagy may be a protective effect on PC12 cells treated with different time points of reoxygenation after 2 h OGD. [ABSTRACT FROM AUTHOR]

Alzheimer′s disease (AD) is an age related and progressive neurodegenerative disease. Autophagy is a self-degradative process and plays a critical role in removing long-lived proteins and damaged organelles. Recent evidence suggests that autophagy might be involved in the pathogenesis of AD. β-asarone have various neuroprotective effects. However, the effect of β-asarone on autophagy in amyloid β-peptide (Aβ) induced cell injury is unclear, and little is known about the signaling pathway of β-asarone in autophagy regulation. The aim of the present study was to determine whether β-asarone protects cells from Aβ 1–42 induced cytotoxicity via regulation of Beclin-1 dependent autophagy and its regulating signaling pathway. We examined effects of β-asarone on cell morphology, cell viability, neuron specific enolase (NSE) levels, autophagosomes and regulating Beclin-1, p-Akt and p-mTOR expressions in Aβ 1–42 treated PC12 cells. We found that β-asarone could maintain the original morphology of cells and increase cell viability and decrease NSE levels significantly. Meanwhile, β-asarone decreased Beclin-1 expression significantly. In addition, β-asarone can increase levels of p-Akt and p-mTOR. These results showed that β-asarone protected cells from Aβ 1–42 induced cytotoxicity and attenuated autophagy via activation of Akt-mTOR signaling pathway, which could be involved in neuroprotection of β-asarone against Aβ toxicity. Our findings suggest that β-asarone might be a potential preventive drug for AD. [ABSTRACT FROM AUTHOR]