EIF2α and caspase-12 activation are involved in oxygen–glucose–serum deprivation/restoration-induced apoptosis of spinal cord astrocytes

Astrocytes play an important role in protecting neurons during ischemia and reperfusion in the central nervous system. Although many studies have shown that oxygen–glucose deprivation (OGD) can induce astrocyte apoptosis, the role of PERK/eIF2α/ATF4 integrated stress response (ISR) in astrocyte apoptosis mediated by oxygen–glucose–serum deprivation (OGSD)/restoration remains uncertain. Astrocytes were subjected to a combination of oxygen, glucose, and serum deprivation for 8 h followed by restoration. Hoechst 33342 staining was performed to quantify apoptotic astrocytes and cell viability was assessed with Cell Counting Kit-8 (CCK8). Immunocytochemical analysis and Western blotting for some related molecules, including pancreatic ER stress kinase (PERK), p-PERK, eukaryotic initiation factor 2 alpha (eIF2α), p-eIF2α, activating transcription factor 4 (ATF4), caspase-12, were examined. Caspase activation and apoptosis were detected in neonatal rat astrocytes from spinal cord subjected to OGSD/restoration. We also observed an increase in cytoplasmic staining of p-eIF2α in astrocytes (8 h OGSD/15 min restoration) compared with that of non-treated cells. In addition, we found the sequential activation of PERK, eIF2α, and ATF4 during OGSD/restoration by Western blotting. These results indicate that both the PERK/eIF2α/ATF4 ISR and activation of caspase-12 may be involved in apoptosis of spinal cord astrocytes induced by OGSD/restoration.