| ObjectiveTo investigate the effects of groundwater on the liver and kidney function of rats in the chromium contaminated area,observe the pathological changes of liver and kidney in rats,and analyze the related mechanisms that may cause liver and kidney damage.MethodsThe groundwater in the chromium-contaminated area was used as the experimental group,and the experimental study was carried out with different concentrations of potassium dichromate as the positive control group.Ten healthy SD pregnant rats were randomly divided into 5 groups(blank group,groundwater group,low chromium group,medium chromium group,high chromium group).The pregnancy rats after production are fed distilled water,chromium contaminated area groundwater(the chromium content is 28.64mg/L),and potassium dichromate solution that the chromium contents are 0.8mg/kg、4mg/kg、20mg/kg.On day 21,mice were weaned and fed directly to mice which the dose is unchanged and once a day for 6 months.During the gavage,observe the behavioral activities,hair color,body weight and other growth conditions of progeny rats.After 180 days of gavage,the offspring rats were placed in metabolic cages,fasting but not water.The rats were anesthetized the next day,and the rats’ blood,liver and kidney tissues were taken after dissection;Determination of chromium in liver and kidney tissues by atomic absorption spectrometry(graph furnace method);Serum total protein(TP),albumin(ALB),globulin(GLB),glucose(GLU),urea(Urea),creatinine(SCr)and aspartate aminotransferase(AST)and valley were detected by automatic biochemical analyzer.Alanine aminotransferase(ALT),alkaline phosphatase(ALP)viability;Make the liver and kidney into slices,the pathological changes of liver and kidney tissues were observed by hematoxylin-eosin staining(HE)staining;Detection of Caspase-3 and PARP expression in liver and kidney by immunohistochemistry;Observation of the degree of apoptosis of rat hepatocytes and renal cells by TUNEL staining.The data were analyzed by SPSS20.0 software.The measurement data were expressed by x ±S.One-Way ANOVA was used to compare the multiple groups.The normality test and the homogeneity test of variance were performed for each analysis.Brown-Forsythe test or rank sum test is used when the variance is not uniform.If there is a difference between the groups,a pairwise comparison is made.The SNK method(q test)and the LSD test method are used for the comparison between the two groups.The Dunnett’s T3 test is used when the variance is not uniform,and the test level α=0.05.The same indicator between multiple groups of means was compared at different time points using repeated measures of variance analysis(Repeated Mwasures).Results1.During the experiment,the rats in the blank group were white,active,and the diet and weight gain were normal;Compared with the blank group,the groundwater group rats was slightly dark yellow in color,slightly slow in response,and slightly delayed in growth;With the increase of the number of days of exposure,the rats in the potassium dichromate exposure group showed physiological phenomena such as dark brown color,loss of appetite and slow response.The body weight was slower than that in the blank group,and the difference was statistically significant(P<0.05).2.Compared with the blank group,the difference in the content of chromium in the liver between the groundwater group and each dose of potassium dichromate exposure group was statistically significant.With the increase of the dose,the content of chromium in the liver of the offspring rats showed an upward trend(P<0.05).After comparing the two groups,the Dunnett’s T3 results showed that there was no significant difference in the content of chromium in the liver between the groundwater group and the low chromium group(P>0.05).The difference of the chromium content in the liver between the other groups was statistically significant(P<0.05).3.Compared with the blank group,the content of chromium in the kidneys of the groundwater group and each dose of potassium dichromate was increased,and the dose increased with the dose.The content of chromium in the kidney of the rats was increased,and the difference was statistically significant(P<0.05).After comparison between the two groups,the Dunnett’s T3 results showed a blank group,and the difference in renal chromium content between the groundwater group and the potassium dichromate-treated group was statistically significant(P<0.05).4.Compared with the blank group,the contents of TP,ALB,GLB,GLU and Urea in the serum of the groundwater group and each dose of potassium dichromate were increased,and the difference in the mean was statistically significant(P<0.05).The indicators with statistically significant differences in the overall mean of each group were compared in pairs.The result is as follows:The TP index showed that there was a statistically significant difference in the mean mean between the middle chromium group and the high chromium group(P<0.05).The ALB and GLB indicators showed that there was no significant difference in the mean mean between the blank group and the groundwater group(P>0.05).There was no significant difference between the groundwater group and the low chromium group(P>0.05).The difference in the mean number between the groups was statistically significant(P<0.05).The GLU index showed that there was no significant difference in the mean mean between the middle chromium group and the high chromium group(P>0.05),but the difference between the overall mean and the other three groups was statistically significant(P<0.05).Urea indicators showed that the overall mean difference between the groundwater group and the potassium dichromate group was statistically significant(P<0.05).The serum and AST,ALT,and ALP activity values of the groundwater group and each dose of potassium dichromate exposure group were higher than those of the blank group.The difference between the total mean of the potassium dichromate exposure group and the blank group was statistically significant.(P<0.05).5.The results of HE staining showed that under the light microscope,the liver cells of the blank group were arranged neatly,and they were strip-like,and the cytoplasm was round and full.The hepatocytes of the groundwater group showed eosinophilic changes and were irregularly arranged.With the increase of the concentration of potassium dichromate,the liver cells of rats showed different degrees of eosinophilic changes,disordered arrangement,increased cytoplasmic gap,and even vacuolization.In a few high-chromium rats,hepatic sinus expansion,congestion and a small amount of exudative hemorrhage,occasionally necrotic foci;Under the light microscope,the glomerular structure was intact,the renal tubular epithelial cells were arranged neatly,regularly and orderly.The renal tubules of the groundwater group showed a glassy change and a small renal tubular type appeared.In the low-chromium group,the renal tubules were disordered,and a small number of renal tubules appeared.The glass-like changes of the renal tubules in the medium-chromium group were more obvious,and the arrangement of the renal tubules was more disordered.In the high-chromium group,the tubules of the renal tubules increased,and the glomeruli contracted slightly.6.Immunohistochemistry results show,Caspase-3 and PARP-positive cells were observed occasionally in the liver of the blank group.In the groundwater group,a few positive cells were observed.As the concentration of potassium dichromate was increased,the number of positive cells gradually increased;Immunohistochemistry results show,Caspase-3 and PARP-positive cells were observed occasionally in the kidneys of the blank group.Compared with the blank group,activated Caspase-3 and PARP positive cells increased.In the potassium dichromate-treated group,the number of activated Caspase-3 and PARP-positive cells increased gradually.7.TUNEL cell apoptosis experiment of Liver shows:The apoptosis of hepatocytes in the blank group was minimal,and the apoptotic rate was(0.94±0.02)%.The number of hepatocyte apoptosis in the groundwater group and potassium dichromate exposure group increased,and the apoptosis rate was(10.54±0.46)%,(11.03±0.39)%,(16.45±0.27)%,(25.41±0.25)%,the overall difference in apoptotic rate is statistically significant(P<0.05);TUNEL cell apoptosis experiment of Renal shows:The apoptosis of renal cells in the blank group was minimal,and the apoptotic rate was(0.78±0.17)%.The number of renal cell apoptosis in the groundwater group and potassium dichromate exposure group increased gradually,and the apoptosis rate was(12.30±0.28%),(15.18 ± 1.17)%,(20.33 ± 0.71)%,(27.13 ± 0.63)%,the overall difference in apoptotic rate is statistically significant(P<0.05).Conclusions1.Long-term exposure to hexavalent chromium can increase the content of TP,ALB and GLB in serum,decrease the content of GLU and Urea,and increase the vitality of AST,ALT and ALP.2.The chromium content in groundwater in the chrome-contaminated area is seriously exceeded.Due to the accumulation of hexavalent chromium in the liver and kidney,long-term exposure can cause serious damage to the liver and kidneys.Its mechanism of action may be related to hepatic and renal cell apoptosis induced by hexavalent chromium. |
