Isoda_2005_Environ.Sci_12_9

Organophosphorous pesticides are currently widely used in China to help boost agricultural production. However, these pesticides pose various threats to organisms, including humans, and are thus a cause of concern. Five organophosphorous pesticides, monocrotophos, omethoate, parathion-methyl, phoxim and dichlorvos, were examined for their effects on mammalian cell lines to determine their potential impact on physiological functions in vivo. Results show an increased proliferation of MCF-7 cells treated with 0.2 microM monocrotophos or 0.4 microM omethoate, suggesting that these compounds can induce breast cancer cell proliferation at relatively low concentrations. Murine primary spleen cells markedly decreased in number starting at a pesticide concentration of 0.01 microM; no cytotoxicity was observed below 0.001 microM. BALB/c3T3 murine fibroblasts treated with 0.25 microM monocrotophos showed enhanced DNA synthesis, while those treated with the other pesticides showed results similar to that of the control. The different pesticides reduced the acetylcholinesterase (AChE) activity of the rat neuronal cell line PC12 in a dose-dependent manner up to 100 microM. Parathion-methyl and phoxim showed acute toxicity at 0.01 microM. Finally, phoxim and parathion-methyl significantly reduced the transepithelial electrical resistance (TEER) of human intestinal Caco-2 cells, indicating that these pesticides can disrupt the tight-junction permeability of cell monolayers. These in vitro assays, which are rapid, reproducible, simple and inexpensive, clearly show the effects of organophosphorous pesticides on mammalian cells and suggest the potential impact of these pesticides on organisms in vivo.