Effects Of Ellagic Acid On Oxidative Damage Of Intestinal Mucosal Barrier In Piglets

In the swine industry,oxidative stress is universal,highly pathogenic and highly concealed.Intestinal development is the core of the rapid growth of piglets,and the intestine is one of the major target organs attacked by hydroxyl free radicals.Ellagic acid(EA)is a class of plant polyphenolic extracts with strong antioxidant properties.In this study,paraquat(PQ)-induced porcine intestinal epithelial cell line IPEC-J2 cells and weaned piglets were used as models to explore the effect of EA on intestinal oxidative stress injury repair.(1)Alleviate of EA on oxidative damage of intestinal epithelial cells in pigIPEC-J2 cells were cultured in vitro and induced by 60 μM PQ for 6 h,and then 0,1,2,and 4 μM EA were added to the culture medium,respectively.Whether EA has antioxidant activity in IPEC-J2 cells was investigated by this trial.The results showed that compared with the control group,PQ significantly decreased the cell viability and superoxide dismutase(SOD)activity of IPEC-J2(P < 0.05),while significantly increased the level of malondialdehyde(MDA)(P < 0.05).In addition,adding PQ increased the level of ROS in IPEC-J2 cells.Compared with the PQ group,1,2,and 4 μM EA treatments significantly increased the cell viability of IPEC-J2(P < 0.05).Adding 1,2,and 4 μM EA significantly decreased the MDA level in IPEC-J2(P < 0.05),but had no significant effect on SOD activity(P > 0.05),in which4 μM EA was the optimal concentration.Adding 4 μM EA reduced the level of ROS in cells.In conclusion,in PQ induced IPEC-J2 cells,EA reduced cellular levels of reactive oxygen species and lipid peroxidation,as well as increased intestinal epithelial cell viability.(2)Regulation of EA on intestinal oxidative stress injury in pigletsForty piglets weaned at 21 days of age and randomly divided into 5 groups,which were fed the basal diet(control group)and diets supplemented with 0.005%,0.01% and 0.02% EA(EL,EM,EH groups)respectively.On the 18 th day of the experiment,4 mg/kg PQ or saline was injected intraperitoneally,blood was collected on the 21 st day of the experiment,and then slaughtered to collect jejunum and ileum.This trial was conducted to study the effect of EA on intestinal barrier oxidative injury repair in weaned piglets.The results showed that EL and EH treatments eliminated PQ-induced growth inhibition of piglets(P < 0.05),EM increased SOD activity in serum(P < 0.05),and EM and EH decreased MDA levels in serum(P < 0.05).Supplementations of 0.005% EA(EL)and 0.01% EA(EM)promoted nuclear translocation of nuclear factor erythroid 2-related factor 2(Nrf2)in jejunal and ileal mucosa.Meanwhile,EL and EM increased heme oxygenase-1(HO-1)and quinone oxidoreductase-1(NQO1)protein abundances(P < 0.05).Treatment of EL,EM,and EH ameliorated intestinal crypt deepening,goblet cell loss,and villus morphological damage induced by PQ(P < 0.05).EL,EM,and EH increased the relative expressions of tight junction proteins(P < 0.05)in jejunum and ileum,and EM and EH treatments significantly decreased serum diamine oxidase(DAO)levels(P <0.05).In conclusion,EA could effectively alleviate the growth inhibition of piglets caused by oxidative stress,increase the activity of antioxidant enzymes and reduce the level of lipid peroxidation through the Nrf2 signaling pathway.At the same time,EA treatment enhanced the integrity of tight junction structure and reduced the intestinal barrier permeability,which alleviated the oxidative stress and promoted intestinal injury repair in weaned piglets.