Effect Of Oxidative Damage Of Liver And Kidney In Mice Caused By Bisphenol A Exposure

Objective：To observe the oxidative damage and the change of tissue morphology in miceliver and kidney caused by low doses of BPA. To provide a basis for thecomprehensive evaluation of low doses of BPA exposure.Methods：1.72aged4weeks (KM) male mice of clean grade, were randomly divided into4exposure groups according to body weight, and administered with differentconcentration of corn oil solution with different dose of BPA (0.4μg/kg,4μg/kg,40μg/kg) by perfusing the stomachs once a day for30days. Execute6mices eachgroups at the time of10days,15days and30days, detect the tissue and take thespecimens. Observe the growth of mices during the experiment.2. Weight the mices at the end of BPA exposure. All mice were sacrificed byneck breaking method, separate the liver and the kidney out of its body, weight themto calculate the relative organ weight (ROW). Hepatic and renal histopathologicalchanges were observed under light microscope by hematoxylin and eosin (HE)stainning. Take some tissues to prepare the homogenate used to analysis biochemicalindex.3. Concentration of10%and1%Liver and kidney homogenates are prepared byfrozen centrifugal. Determin the activity of superoxide dismutase (SOD) by WST-1assay, determin the activity of CAT by ultraviolet spectrophotometry assay, determinthe activity of GSH-Px by colorimetric assay, determin the content of MDA bycolorimetric assay, determin the content of hydrogen peroxide by spectrophotometryassay, determin the content of hydrogen peroxide and superoxide anion free radicalby colorimetric assay. Results：1. The control group mice are active, while the BPA infected mice reduced theiractivities.There was no abvious differences in each does of groups after infected10days and there was no statistically significant difference compared with the controlgroup (p>0.05); Each infected dose of groups had a difference in the weight gain after15days and30days,and there was a significant different compared with the conctrolgroup（p<0.05）.2. Each infected group had a different in the liver viscera coefficients after10days,15days or30days (p<0.05),and each dose group’s liver viscera coefficients hadobvious differences in different time points (p<0.05).10days later,there was nosignificant difference in each infected group’s kidney viscera coefficients(p>0.05).While15days and30days later,there was a difference in infected group’skidney viscera coefficients (p<0.05).And there were significant differences indifferent time points in each group’s kidney viscera coefficients (p<0.05). Liverpathology observation showed that the liver tissue of the control group is normal, butexposure groups’tissues gradually appeared inflammatory cells invasion,the nucleuspyknosis,large focal degeneration and necrosis with the increse of the infected doseand the prolong of the time. The kidney tissues of each BPA infected group were alsogradually appeared glomerular exudation and renal tubule degeneration.3.The activities of the antioxidant enzymes SOD, CAT and gsh-px had doseeffect relationships with the BPA concentrations;the exposure group was abviousdifferent in15days and30days later and compared with the control group,thedifference was significant(p<0.05).The same dose groups had significant differencesin different time points(p<0.05). In each infected groups, the contents of the oxygenfree radicals OH-, O2-, H2O2and lipid peroxide MDA had dose effect relationshipswith BPA concentrations, and the difference was statistically significant (P <0.05);The same infected dose groups were different in the different time points and thedifference was statistically significant (P <0.05) Conclusions：1. BPA can induce obvious hepatotoxicity on mice. Low dose (0.4μg/kg,4μg/kg,40μg/kg) BPA exposure can cause liver inflammation, epithelial cells of renaltissue water degeneration.2. BPA can induce oxidative damage in liver and kidney on mice. Theconcentration of oxygen free radicals increased, and the activity of antioxidantenzymes decreased with the exposure time increased in liver and kidney in all BPAdose exposure. It is showed that low dose BPA exposure can destroy the balance ofoxidation through oxidative stress, and cause oxidative damage.