| OBJECTIVE To establish animal model and observe the chronic effect of deltamethrin on the behavior; to study morphologic changes, DNA damage and damage repair on liver of test animals induced by deltamethrin; to evaluate DNA damage repair mechanism and significances. METHODS To use the chronic toxicity tests, and 32 female Wistar rats were randomly divided into four groups. The deltamethrin exposure doses were separately 0,1.56,3.12,6.25 mg/kg by gavage for twenty-four weeks. The changes of rats behavior were observored in the periods of experiment. In the end the rats were fasting but drunking water free. After 24 hours, they were killed, and the liver were dislodged and weighted accurately. Observed organ's morphologic changes that stained HE and delected the effects of DM to Maleic Dialdehyde, Glutathione peroxidase and Superoxide Dismutase activities in their liver. DNA damage was detected by Single cell gel electrophoresis (Comet assay) and Expression of MGMT and XRCC-5 were assayed by RT-PCR. RESULTS The organ coefficient of liver was increased in experimental groups compared with the control groups (P<0.05), morphological observation by HE staining shows there were more abnormities in DM groups, dropsy were found in hepatic cells, Lipid droplets were found within hepatocytes, congestion were found in the hepatic sinusoid of rats. The contents of MDA,GSH-PX and SOD in test group were significant different from the control group (P<0.05). Tail DNA%,Tail Moment and Olive Tail Moment of liver cells in deltamethrin exposed rats were higher than that in control group(P<0.05). The mRNA expression of MGMT in the low dose group was higher than that in the control, no significant difference of expression of XRCC-5 was found between test groups and control group (P>0.05). CONCLUSION Deltamethrin might cause the changes of MDA, GSH-PX and SOD in liver of rat, further decrease the antioxidation of the body, finally lead to DNA damage of liver, and cause DNA damage repair system. |
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