Avaliação in vitro do efeito pró-inflamatório e oxidativo dos pesticidas mancozebe, clorotalonil e tiofanato metílico

Abstract

Pesticides are widely used in agriculture and public health for pest control and prevention. The indiscriminate use of these compounds can trigger environmental contamination by pesticides and increase the risk of human exposure. Human exposure to pesticides can occur directly, through occupational activity, or indirectly, through the environment and food. Chronic exposure to pesticides may result in neurological, reproductive, teratogenic and immunological disorders. Mancozeb, chlorothalonil and thiophanate methyl are fungicides widely used in the world. Despite their characteristics of low acute toxicity and low persistence in the environment, in vitro and in vivo studies demonstrate the cytotoxic effects of these compounds. However, the immunological effects that these pesticides can trigger are unexplored. Therefore, the objective of this study was to evaluate in vitro the pro-inflammatory and oxidative effects of mancozeb, chlorothalonil and thiophanate methyl pesticides. RAW 264.7 (ATCC® TIB-71™) macrophages were exposed to different concentrations (0.1-100 μg/mL) of each pesticide for 72 hours, and maintained in 5% CO2 atmosphere at 37°C. The pesticides were dissolved in dimethylsulfoxide, which was used as negative control. Phytohemagglutinin was used as positive control for inflammatory activation. The evaluation of cell proliferation, oxidative metabolism and pro-inflammatory cytokines (IL-1β, IL-6, TNF-α and IFN-γ), anti-inflammatory cytokine (IL-10) and caspases (Casp1, Casp3, Casp8) levels were performed by fluorimetric and molecular tests. The results showed a significant pro-inflammatory effect of mancozeb, chlorothalonil and thiophanate methyl pesticides at respective concentrations of 1, 3 and 100 μg/mL, with increase in cell proliferation and pro-inflammatory cytokines and caspases levels. However, the oxidative effect was only observed in macrophages exposed to chlorothalonil at 3 μg/mL. Thus, in these analysis conditions, the studied pesticides acted by activation of the immune system. The results found contribute to better understanding of immunological effects caused by exposure to these pesticides.