The Toxic Effcts And Mechanism Of Two Environment Hormones Malathion And Atrazine On Fish Cell

Environmental hormones (EHs), also called environmental endocrine disruption chemicals (EDCs), have been confirmed to be a group of newly environmental contaminants and EHs have raised increasing concern from every walk of life. It is considered that pollution of EHs has become one of three great global environmental problems the same as global climatological change and ozonosphere destruction. They can cause endocrine confusion of the healthy body. Atrazine (2-chloro-4-ethylamino-6-isopropoylamino-s-triazine) is a pre- and postemergence herbicide for the control of annual and perennial grass and annual broad-leaved weeds. Malathion is widely used in many countries to control mosquitos and rice pests. In present study, a grass carp(ctenopharyngodon idellus) cell culture ZC7901 was used as an in vitro model system to study the toxic effects of malathion and atrazine.In part I, we studied the cytotoxic effects of malathion and atrazine. The results in inverted microscope showed that the viability of cells stressed by malathion or atrazine have been affected clearly and the percentage of cell adherence have been decreased. The MTT cleavage assay indicated that malathion or atrazine can inhibite the cells growth and this inhibition are dose- and time-dependent. So we can conclude that high concentration of the residue of malathion or atrazine and long time accumulation of the residue are adverse to the growth of cells of grass carp. Moreover, the results described that the IC50 value in 12hr to 72hr of malathion and atrazine on ZC7901 cells were 34.935 to 3.04mg/L and 198.980-11.567mg/L, indicating that malathion is more toxic than atrazine.In part II, we found that malathion and atrazine can all result in apoptosis of fish cell ZC7901. The results through fluorescence microscope and confocal laser microscope and transmissional electronmicroscope showed that the culture chemically stressed by malathion or atrazine exhibited cell death accompanied by various morphological alterations such as nuclear condensation, chromatin abutted sharply against nuclear membrane and develop into distinct apoptotic-like bodies, which were charateristic features seen in apoptosis. By agarose gel electrophoresis, DNA ladderswas clearly visualized, furthermore, the study of malathion or atrazine treatment showed that there were better relationships between the cell apoptosis and concentration and time, namely that higher concentration malathion or atrazine treatment can result in apoptosis rapidly and contrarily lower concentration malathion or atrazine treatment can induce apoptosis tardily.In part III, the changed of intracellular Ca2+, O2-, H2O2, ATP and the mitochondria membrane potential in the apoptosis induced by malathion or atrazine were investigated. The results showed that the intracellular Ca2+ content increased in 24hr, so did O2, H2O2 in 36hr. then decreased. But mitochondria membrane potential and ATP content kept decreasing quickly. These data indicated that the intracellular Ca2+, O2-, H2O2, ATP and mitochondria membrane potential all played roles in apoptosis of malathion or atrazine inducing, maybe the oxidative stress is the way of apoptosis.