A Study On The Repairing Effect Of Sanguinarine On Intestinal Mucosal Injury In Immunological Challenge Weaned Piglets

This study aimed to investigate the protective effect of sanguinarine on the intestinal mucosal barrier function in the weaned piglets challanged with lipopolysaccharide(LPS),and explore the role of TLR4/NF-κB signaling pathway in sanguinarine(SAG)-mediated protection of intestinal mucosal function.(Method)A total number of twenty-four healthy “Duroc×Landrace×Yorkshire” weaned piglets with an average intial weight(6.20 ± 0.09 kg)and age(21 ± 1 d)were randomly assigned to four groups: the control group(CON+Saline)(fed basal diet),the CON+LPS group(fed basal diet and injected intraperitoneally with 100 μg/kg BW LPS),the SAG+Saline group(fed basal diet containing 50mg/kg SAG)and the SAG + LPS group(fed basal diet containing 50 mg/kg SAG and injected intraperitioneally with 100 μg/kg BW LPS).There were six replicates per group and one piglet per replicate.On day 14 and 21,piglets were injected intraperitoneally with 100 μg/kg BW LPS or an equivalent amount of sterile saline,the experiment lasted for 21 days.Daily feed intake and diarrhea scores of piglets were recorded;blood samples were collected 3h after LPS challenge,and intestinal samples were collected 12 h post-administration of LPS on day 21.The main results were shown as follows:1)SAG supplementation significantly increased the final weight(FW),average daily feed intake(ADFI)and average daily gain(ADG)(P < 0.05),and significantly reduced feed/gain(F/G)(P < 0.05).Compared with the CON+LPS group,the FW、ADFI、ADG of piglets significantly increased(P < 0.05)and the F/G significantly reduced(P < 0.05)in the SAG+LPS group;2)SAG supplementation significantly increased the concentration of serum Immunoglobulin M(IgM),Immunoglobulin G(IgG)and Interleukin 10(IL-10)of piglets(P < 0.05),significantly reduced the concentration of serum Interleukin 1β(IL-1β),Interleukin 6(IL-6)and Tumor necrosis factor α(TNF-α)of piglets(P < 0.05).Compared with the CON+LPS group,the concentration of serum IL-1β、IL-6 and TNF-α significantly reduced(P < 0.05)and the concentration of IL-10 significantly increased(P < 0.05)in the SAG+LPS group;3)SAG supplementation significantly reduced the concentration of D-lactate(D-LA)and the activities of diamine oxidase(DAO)in serum(P < 0.05),compared with the CON+LPS group,the concentration of D-LA and the activities of diamine oxidase were significantly reduced in the SAG+LPS group(P < 0.05);4)SAG supplementation significantly increased the villus height(VH)and the ratio of villus height to crypt depth in duodenum,jejunum and ileum of piglets(P < 0.05),and reduced the crypt depth(CD)of duodenum(P < 0.05),tended to reduce the CD of ilem(P = 0.074).Compared with the CON+LPS group,the VH and V/C of duodenum,jejunum and ileum were significantly increased(P < 0.05),and the CD was significantly reduced in duodenum(P < 0.05)in SAG+LPS group;5)SAG supplementation significantly increased the expression of ZO-1,Occludin and Claudin-1 mRNA in duodenum mucosa(P < 0.05),significantly increased the expression of Occludin and Claudin-1 mRNA in jejunum mucosa(P < 0.05),significantly increased the expression of Claudin-1 mRNA in ileum mucosa(P < 0.05),and tended to increase the expression of ZO-1 mRNA in jejunum mucosa of piglets(P = 0.052).In addition,compared with the CON+LPS group,the expression of ZO-1,Occludin and Claudin-1 mRNA were significantly increased in duodenum and jejunum mucosa of piglets in the SAG+LPS group(P < 0.05);6)SAG supplementation significantly reduced the expression of IL-1β,IL-6 and TNF-α mRNA in duodenum,jejunum and ileum mucosa(P < 0.05),and significantly increased the expression of IL-10 mRNA in duodenum and ileum mucosa of piglets(P < 0.05).Meanwhile,compared with the CON+LPS group,the expression of IL-1β,IL-6 and TNF-α mRNA in duodenum and jejunum mucosa were significantly decreased(P < 0.05),while the expression of IL-10 mRNA in duodenum and ileum mucosa(P < 0.05)in the SAG+LPS group;7)SAG supplementation significantly down-regulated the expression of NF-κB mRNA in duodenum,jejunum and ileum mucosa(P < 0.05),significantly down-regulated the expression of TLR4 mRNA in jejunum mucosa(P<0.05),significantly up-regulated the expression of IκB mRNA in duodenum,jejunum and ileum mucosa(P < 0.05),and tended to down-regulate the expression of TLR4 mRNA in duodenum mucosa of piglets(P = 0.052).Meanwhile,compared with the CON+LPS group,the expression of TLR4 and NF-κB mRNA in duodenum,jejunum and ileum mucosa were significantly down-regulated(P < 0.05),while the expression of IκB mRNA in duodenum,jejunum and ileum mucosa were significantly up-regulated(P < 0.05).Taken together,this study revealed that SAG could regulate the transcription of inflammatory cytokines by inhibiting the activation of NF-κB signaling pathway,which prevent the overproduction of inflammatory cytokines to alleviate the decline of intestinal mucosa tight junction protein induced by LPS,and finally improve intestinal mucosal barrier function,relieve piglet diarrhea,and promote piglets growth.