Mechanisms of primary-cultured hepatocyte apoptosis induced by dimethoate in rats.

To study the effects of dimethoate on liver cell apoptosis,dimethoate was added to hepatocyte culture fluid of rats with final concentration of 0,3,10,30,100 and 300 μmol/L,respectively.After 12 h and 24 h exposure,apoptotic cells were observed by electron microscope and fluorescence microscope,apoptosis rate was analyzed by annexin V/PI method;intracellular Ca2+ concentration,reactive oxygen species(ROS) and mitochondria membrane potential(Δψm) changes were analyzed by Fluo-2/AM,dichlorofluorescin diacetate(DCFH-DA) and rhodamine 123 method respectively.The results showed that after 12 h and 24 h exposure,ultrastructural changes of apoptotic cells induced by dimethoate were observed,cell apoptosis rate increased significantly,experimental groups(apart from the group with 3 μmol/L) had significant(P0.05 or P0.01) differences with control group and followed dose proportionality.Intracellular Ca2+ concentration was significantly(P0.01) high in group with 3 μmol/L was than that of control group,and then decreased with increasing dosage.Intracellular ROS level increased with increasing dosage and time of exposure in the range of 3-100 μmol/L;however,ROS level decreased slightly in group with 300 μmol/L.Not concluding group with 3 μmol/L,the differences between control group and experimental groups were significant(P0.01).Δψm decreased continuously except group with 300 μmol/L after 24 h exposure.It was concluded that low dosage of Dimethoate can induce liver cell apoptosis,and intracellular Ca2+,ROS and Δψm may participate this process.