Effect of iprodione, a dicarboximide fungicide, on primary cultured rainbow trout (Oncorhynchus mykiss) hepatocytes

As is known from literature, iprodione, a dicarboximide fungicide, has a hi ghly specific action, with a capacity to cause oxidative damage through pro duction of free oxygen radicals (ROS), but it does not appear to be species selective. Since this substance is able to diffuse in water, evaluation of its capacity to induce oxidative damage in an aquatic organism such as the rainbow trout (Oncorhynchus mykiss) was considered of particular interest. A study was, therefore, undertaken to investigate the effect of iprodione on free radicals (ROS) and malondialdehyde (MDA) production, reduced glutat hione (GSH) content and catalase activity (CAT), in primary cultured trout hepatocytes, following treatment with 0.2, 0.3 and 0.4 mM concentrations fo r a 24-h period. The iprodione 0.3 and 0.4 mM concentrations increased both ROS and MDA production and decreased GSH content and CAT activity. These r esults suggest that iprodione is able to produce oxidative damage in primar y cultured fish hepatocytes, thus confirming that its action is specific, b ut not species selective. It is also well known that ROS production in fung i is due to interaction with the flavin enzyme NADPH cytochrome c reductase to the extent that the normal electron flow from NADPH to cytochrome c is blocked. In contrast, we observed that, in primary cultured trout hepatocyt es, iprodione appears to have no effect on NADPH cytochrome c reductase act ivity. It is, therefore, possible to presume that the mechanism of oxidativ e damage in trout hepatocytes differs from that observed in fungi. Moreover , our experiments also demonstrate that iprodione is able to induce 'in vit ro' CYP1A1, leading to the conclusion that the production of ROS is due to this phenomenon. (C) 2000 Elsevier Science BN. All rights reserved.