Pesticide Mixtures Potentiate the Toxicity in Murine Thymocytes

Cultures of thymocytes from mice were exposed to lindane, permethrin, or malathion alone or in combinations of two of the pesticides. Individual exposures caused cell death from necrosis and apoptosis. Greater than additive effects for both apoptosis and necrosis were demonstrated when thymocytes were exposed to binary mixtures of pesticides. DNA fragmentation, shown by ladder formation on gel electrophoresis, which is an indicator of cell death from apoptosis was found for individual pesticides and was increased in the mixtures of pesticides. All the pesticides were considered to be highly immunotoxic. At least part of the cytotoxicity of the compounds was deemed to be from stimulation of apoptosis. For lindane, the mixed oxidase system seems to be induced, adding to the cytotoxicity of that compound when pesticide exposures were combined.