Mechanism of potentiation of endosulfan cytotoxicity by thiram in Ehrlich ascites tumor cells

Cytotoxicity of the two pesticides, thiram and endosulfan, have been studied in Ehrlich ascites tumor cells. Thiram cytotoxicity was much lower than that of endosulfan with LC50 (1 h exposure) of 4.02 and 1.12 mM, respectively. The cytotoxic action of the pesticides on the cells were characterised by glutathione depletion, induction of reactive oxygen species (ROS). The cell death induced by the pesticides was of necrotic type as confirmed by lactate dehydrogenase (LDH) leakage. At non-cytotoxic concentration, thiram potentiated the cytotoxicity of endosulfan when cells were exposed to a mixture of both chemicals. The mechanisms involved in the potentiation of cytotoxicity include excessive glutathione depletion and induction ROS which were higher than the additive effects of individual chemicals. The study demonstrates the importance of pesticide interactions in toxicity risk assessment.