Effects Of T-2 Toxin Gavage To Mice On Hepatic Glycolipid Metabolism And Intestinal Barrier Function In Young Mice

T-2 toxin is one of the most toxic mycotoxins,belongs to group B trichothecenes.It is widely found in crops,such as corn,rye,oats and barley,and it is harmful to the health of human and animals.Most of T-2 toxins are absorbed and degraded in the intestine,cause toxicity to the animal’s digestive system and liver.It has been shown that T-2 toxin can cross the placental barrier,enter the fetus from the pregnant mother and threaten fetal health.However,studies on the effects of T-2 toxin exposure on the offspring of pregnant mothers are still quite limited.Therefore,in this study,pregnant mice were used as subjects.T-2 toxin were administrated to mice to clarify the effects of maternal T-2 toxin gavage on the intestine and liver of pups at different stages.In addition,combined with vitro experiments to further clarify the mechanism of T-2 toxin damage to intestine.The main results are as follows:1.Effects of T-2 toxin gavage to mice on hepatic glycolipid metabolism in young miceThis study aims to investigate the toxic effects of T-2 toxin gavage to mice during gestational and lactating period on hepatic glycolipid metabolism in young mice.The thirty pregnant mice were given 0,0.005 and 0.05 mg of T-2 toxin/kg bw daily through oral administration from late gestation(GD 14)to the lactation(LD 21).On PND 21,PND 28 and PND 56,young mice(n=6,three male and three female)were selected from 0,0.005 and 0.05 mg/kg T-2 toxin treatment groups.All animals were anesthetized with ether and sacrificed by cervical dislocation,livers and serum were collected for further analysis.The results showed that compared with the control group,T-2 toxin treatments significantly reduced the body weight of offspring in different periods(P<0.05).Serum biochemical analysis found that compared with the control group,the levels of high-density lipoprotein cholesterol(HDL-C)in the T-2 toxin groups of PND 21 mice were significantly decreased(P<0.001),triglycerides(TG),total protein(TP)and glucose in the 0.05 mg group were increased significantly(P<0.001).Compared with the control group,T-CHO levels in PND 28 mice were significantly increased in T-2 toxin groups(P<0.001),HDL-C level was significantly increased in the 0.005 mg group(P<0.05),TG and glucose levels were increased significantly in the 0.05 mg group(P<0.001).Compared with the control group,albumin levels in PND 56 mice were significantly increased in the T-2 toxin group(P<0.01),and HDL-C and glucose levels were significantly decreased in the 0.05 mg group(P<0.05).Histological observation of the liver revealed that infiltration of inflammatory cells,congestion of hepatocytes,and deposition of large amounts of lipids in the liver were observed in T-2 toxin treatments groups.Measurement of liver lipid contents showed that compared with the control group,the levels of TG and LDL-C in the liver of PND 21 mice were significantly increased in the 0.05 mg group(P<0.01).The level of LDL-C in liver of PND 28 mice was significantly increased in the 0.005 mg group(P<0.01).RT-PCR results showed that T-2 toxin treatment significantly increased the genes expressions associated with glycolipid metabolism in young mice,such as PEPCK,Glut2,Fas,Acox1,PPARa,Srebp1 and CD36.These results demonstrated T-2 toxin gavage to pregnant mice could cause liver glycolipid metabolism disruption in the young mice.2.Effects of T-2 toxin gavage to mice on microorganisms and intestinal barrier function in young miceThis study aims to investigate the toxic effects of T-2 toxin gavage to mice during gestational and lactating period on the integrity of the intestinal barrier and microbial flora in offspring.The results showed that T-2 toxin gavage during pregnancy disrupted the balance of the microbial flora of the pups.Mainly by reducing the relative abundance of beneficial bacteria,such as Bacteroides,Lachnospiraceae,and increasing the relative abundance of harmful bacteria,such as Proteobacteria,Staphylococcus and Escherichia-Shigella.Morphological observation of the ileum of the pups showed that compared with the control group,villous adhesions and the vacuoles in the villous tissue in the T-2 toxin groups were obvious.RT-PCR results showed that compared with control group,T-2 toxin significantly decreased the genes expressions associated with intestinal barrier function and inflammation in PND 21 pups,such as Occludin,Claudin,ZO-1,IL-6,TNF-α and IL-10(P<0.05,P<0.01,P<0.001),the expressions of Occludin,Claudin,ZO-1,IL-6.TNF-α and IL-10 in PND 56 pups were significantly increased(P<0.001).These results demonstrated T-2 toxin gavage to pregnant mice would cause damage to the ileum epithelium of the pups and impaired barrier function,which may be due to the reduction of beneficial bacteria in the intestine and the increasing of harmful bacteria,which may cause intestinal inflammation,leading to decrease intestinal immunity and damage to the intestinal mucosa.On PND 56,compared with control group,the genes associated with intestinal barrier function and inflammation were significantly increased,which may be due to the strengthening of the body’s self-recovery mechanism,and the intestine initiates self-repairing functions.3.Effects of T-2 toxin on inflammation in porcine jejunal epithelial cells(IPEC-J2)In vivo experiments of mice,we found that T-2 toxin gavage damage the intestinal mucosal barrier and cause intestinal inflammation.The toxicity of mycotoxins have relationship with oxidative stress,which can cause intestinal epithelial cell apoptosis and cause intestinal inflammation.Therefore,T-2 toxin may damage the intestine through oxidative stress.This experiment took intestinal porcine epithelial cells(IPEC-J2)as the research object,exploring the effects of T-2 toxin on intestinal inflammation and its mechanism.The results suggested that T-2 toxin(4 ng/mL)treated IPEC-J2 cells for 12 h caused oxidative stress in the IPEC-J2 cells,such as significantly increased the cell MDA concentration and ROS level(P<0.001),and significantly decreased T-SOD and CAT concentrations(P<0.01).NAC(4 mM),an inhibitor of ROS,significantly decreased the MDA concentration and ROS level(P<0.01,P<0.001),and increased T-SOD and CAT concentrations(P<0.01,P<0.001).RT-PCR results demonstrated that T-2 toxin treatment reduced the genes expressions of Occludin,Claudin and ZO-1(P<0.05,P<0.01),and promoted the genes expressions of IL-6 and TNF-α(P<0.05,P<0.001).After adding NAC to suppress ROS,genes expressions IL-6 and TNF-α were decreased but no significance,IL10 was significantly increased(P<0.05).Protein immunofluorescence results showed that compared with the control group,T-2 toxin group upregulated the expression of nuclear transcription factor κB(NF-κB)protein in IPEC-J2 cells(P<0.01)，while the expression of NF-κB protein was decreased after the addition of NAC(P<0.01).These results demonstrated T-2 toxin induces inflammatory damage to IPEC-J2 cells by activating ROS/NF-κB signaling pathway.In summary,T-2 toxin gavage to mice during gestational and lactating period will affect the liver lipid metabolism and intestinal barrier function of offspring.However,within a certain concentration range(0.05 mg/kg),the body itself has certain repair function.The vitro studies found that T-2 toxin destroyed the intestine mainly by increasing ROS production and prompting the expressions of genes and protein involved in inflammation,causing intestinal epithelial cell inflammation.