POSSIBLE INVOLVEMENT OF CATALASE IN THE PROTECTIVE EFFECT OF INTERLEUKIN-6 AGAINST 6-HYDROXYDOPAMINE TOXICITY IN PC12 CELLS

We examined the effects of various neurotrophic factors and cytokines on 6-hydroxydopamine (6-OHDA)-induced toxicity in PC12 cells. Exposure of PC12 cells to 6-OHDA resulted in a concentration- and time-depende nt cell death, as evidenced by the release of lactate dehydrogenase in to the culture medium. Addition of catalase, but not superoxide dismut ase, to the culture medium protected PC12 cells from the 6-OHDA-induce d toxicity. Interleukin (IL)-6 provided a dose-dependent protection ag ainst the 6-OHDA toxicity, as did nerve growth factor (NGF). In additi on, basic fibroblast growth factor and dibutyryl cyclic AMP partially protected PC12 cells from 6-OHDA toxicity. Neither IL-1 alpha, IL-2, I L-4, transforming growth factor-beta, nor leukemia inhibitory factor h ad any effect. The protective effect of IL-6 was attenuated by 3-amino -1,2,4-triazole, an inhibitor of catalase. These results suggest that IL-6 may protect PC12 cells against the 6-OHDA toxicity by activating free radical detoxifying mechanisms, such as catalase activity. (C) 19 97 Elsevier Science Inc.