| At present,the mycotoxin pollution of cereal food and dairy products is common.Aflatoxin M1(AFM1)and ochratoxin A(OTA)are two common mycotoxins in milk and dairy products.Zearalenone(ZEA)is the most serious mycotoxin in corn and other grains,and also exists in milk and dairy products.When the gut acts as the first line of defense against foreign harmful substances,intestinal cells will be harmed by high concentration of mycotoxins,resulting in intestinal function damage.Liver is the main immune,detoxification and digestive organ of the body,and it will also be exposed to mycotoxin,which has a negative impact on the health of the body.With the change of people's life style,milk,dairy products and grains have become the common food in family.The exposure risk of AFM1,OTA and ZEA in human body can not be ignored.Therefore,the effects of AFM1,OTA and ZEA on the localization of tight junction protein and mucin secretion of Caco-2/HT29-MTX were studied by immunofluorescence,transmission electron micrographs,quantitative polymerase chain reaction(qPCR)analysis and indirect enzyme-linked immunosorbent assay(ELISA).At the same time,the effects of AFM1,OTA,and their mixtures on the metabolism of mice liver and HepG2 cells were investigated using metabolomics approach.The main results are as follows:1.After treatment of Caco-2/HT29-MTX cells with AFM1,OTA and ZEA,the permeability of intestinal epithelial cells was enhanced.Mycotoxin treatment could also change the form of TJ protein and destroy the structure of TJ protein.The mixed mycotoxins had significant regulatory effects on the mRNA expression and protein secretion of MUC5 AC and MUC5 B.The effect of mixed mycotoxins on intestinal barrier function was more significant than that of mycotoxins alone.The damage of mycotoxin to intestinal integrity was related to the change of TJ protein location and the decrease of mucin secretion.2.The activity of AST,the content of TBIL and GGT in serum of AFM1+OTA group were significantly higher than those of control group and individual groups.HE staining showed that inflammatory infiltration and cytoplasmic looseness of hepatocytes appeared in the liver tissue of mouse in the AFM1+OTA group.By oil red O staining,it was found that the mice in the group of single and mixed AFM1 and OTA group showed hepatic steatosis,especially in the group of AFM1+OTA.The metabonomics analysis showed that compared with AFM1 or OTA group,the liver metabolites in the mixed group were significantly affected.The content of lysophosphatidylcholine decreased significantly in the mixed gavage group,while hydroxyphenyllactic acid,L-gamma-glutamyl-L-leucine,proline betaine,L-gamma-glutamyl-L-valine,alpha-linolenic acid and palmitic acid decreased significantly in the mixed gavage group.3.Compared with the control group,the activity of HepG2 cells in AFM1+OTA group decreased gradually.The activity of HepG2 cells in the treatment group with 1 ?g/ml of AFM1 and 0.05 ?g/ml of OTA decreased significantly.HepG2 cells were treated with 1?g/ml AFM1 and 0.05 ?g/ml OTA alone or in combination and analyzed by metabonomics analysis.Which showed that the mixture of AFM1 and OTA had obvious effect on the metabolites in HepG2 cells.Compared with the control group,the content of citric acid,oxoglutaric acid,L-malic acid and pyruvic acid in AFM1+OTA group were significantly decreased.In conclusion,this study concluded that single and mixed AFM1,OTA and ZEA can cause intestinal toxicity.At the same time,single and mixed AFM1 and OTA can cause hepatotoxicity,different metabolites are screened out.Compared with mycotoxin alone,the mixture of mycotoxins can lead to more serious intestinal toxicity and hepatotoxicity. |
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