Effect of endosulfan and malathion on lipid peroxidation, nitrite and TNF-α release by rat peritoneal macrophages

Endosulfan and malathion are organochlorine and organophosphate insecticides, respectively. The toxicity of both the insecticides are well known on non-target organisms. Both endosulfan and malathion are reported to suppress humoral as well as cellular immune responses. We investigated the possible effect of both these insecticides on lipid peroxidation, nitrite production and TNF-alpha generation in rat peritoneal macrophages under in vitro conditions. Rat peritoneal cells were collected and cultured with or without insecticides and relevant stimulants for lipid peroxidation, generation of nitric oxide and TNF-alpha. FeSO4 was used as an inducer for lipid peroxidation and LPS was used to induce nitric oxide synthase and release of TNF-alpha. Lipid peroxidation was assayed by estimating MDA; nitric oxide was determined by estimating nitrite and TNF-alpha by using an assay kit in culture supernatants. Both endosulfan and malathion had no effect on lipid peroxidation. Endosulfan did not have any influence on nitrite production, but suppressed the LPS-induced TNF-alpha generation. Malathion, however, showed a direct suppression on nitrite production and suppression of LPS-induced TNF-alpha generation. This study suggests that functional aberrations of macrophages may contribute significantly to the immunomodulation reported for these insecticides. (C) 2003 Elsevier B.V. All rights reserved.