The cytotoxicity of five organo-phosphorus pesticides at certain biological and biochemical aspects using Chinese hamster ovary cell line CHO-K1

The Cytotoxicity of five organophosphorus pesticides, chlorpyrifos, dichlorvos, monorotophos, fenthion and methidathion was evaluated using COO-K1 cultures. At biological level, the evaluation was followed by the neutral red incorporation [NRI] assay to estimate the midpoint cytotoxicity values [NRI[50]] after 24, 48 and 72 h. At biochemical level, the effect of the estimated NRI[20] values of each substance on the cellular glutathione redox cycle was also studied after 24 Ii of exposure period. The cytotoxicity of the tested pesticides was affected by the period of exposure rather than the protein content in the culture medium. Also, the activity of glutathioge S-transferase was significantly inhihited while glutathione peroxidase was significantly increased. Fenthion and methidathion caused a significant depletion of cellular glutathione. The results demonstrate that the NIH assay in association with the measurement of the glutathione redox cycle using CHO-K1 cells is useful for the prediction of the acute toxicity of pesticides to mammals

Cytotoxic evaluation of certain insect growth regulators and insect sex pheromones in cho-k1 cells

The cytotoxic effects of Diflubeizuron, pyriproxifen as insect growth regulators, ZZ/ZE-7,11-hexadecadienyl acetate, Z-9- hexadecenal and Z-11-hexadecenal as insect sex pheromones were evaluated in vitro using Chinese hamster ovary [CHO-K1] cells. Total cellular protein [TCP] content and methyl tetrazolium [MTT] assays were carried out using serum free medium and medium supplemented with fetal calf serum [FCS, 10%], bovine serum albumin [BSA, 1%] and/or metabolic activation system [S9-mix]. All the tested compounds displayed cytotoxic effects that rise with time exposure. TCP assay exhibited higher sensitivity than MTT assay with all the tested compounds. In presence of the added extracellular proteins and/or metabolic activation system [S9-mix], the cytotoxic effects significantly decreased which indicate that the tested agents may be binding non-specifically with protein and extensive metabolized to less toxic metabolites