Induction of cytokine genes and IL-1α by chemical hypoxia in PC12 cells

The role of cytokine in neuronal injury was examined in rat pheochromocytoma (PC12) cells under chemical hypoxia (i.e. KCN) and glucose deprivation. The mRNA levels of interleukin-1alpha (IL-1α), IL-6, and tumor necrosis factor-alpha (TNF-α) were measured by reverse transcription-polymerase chain reaction (RT-PCR) in PC12 cells exposed to 0.5 mM KCN for various time intervals. Cytokine mRNA levels expressed to peak levels 30 minutes after KCN treatment and declined gradually until 240 min. The IL-1α activity reached the highest levels 2 hr after the same KCN treatment. Under parallel conditions, KCN increased cytosolic free calcium concentration ([Ca2+]i) in the absence of glucose. However, IL-1α mRNA induction by KCN was not altered under calcium-free conditions in PC12 cells, indicating its induction was Ca2+-independent. However, the phosphatidylcholine (PC)-specific phospholipase C (PLC) inhibitor D609 decreased the KCN-induced IL-1α mRNA and protein in PC12 cells suggests that PC-PLC might play a role in cytokine induction during hypoxia.