Diazinon immunotoxicity in mice: modulation of cytokines level and their gene expression

Diazinon is one of the organophosphate pesticides of wide spectrum insect-killing power. Diazinon extensive application as an effective pesticide was associated with direct or indirect modulation of major and vital immune mechanisms. This study addressed the effect of diazinon toxicity on cytokines that are involved in the regulation of innate, cellular and humoral immune responses. Mice intoxicated with 50 mg/kg (1/5 LD50) body weight for 30 days indicated gradual decrease in the level of interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-10 (IL-10), interleukin-12 (IL-12) and interferon-gamma (IFN-gamma) in the splenocytes cultures that were pulsed with phytohaemagglutinin (PHA). Sever suppression of these cytokines was confirmed by the RT-PCR. The level of IL-10 in CD4(+), CD8(+), and B cells indicated significant increase, whereas INF-gamma level was significantly decreased in B cells only. On the molecular level, the INF-gamma mRNA synthesis was significantly increased in all cells subpopulation, whereas, IL-2 mRNA synthesis was only increased in CD4(+). It was shown that diazinon immunotoxicity in mice capable of modulating the major cytokines involved in the regulation of the immune responses. In certain stage of diazinon toxicity, Th2 type responses appeared dominant. Diazinon could accelerate the INF- gamma and IL-2 mRNA synthesis but their translation might be impaired.