Regulatory Effect Of Arginine On The Injury Of Intestinal Barrier Function Via Ppar_γ/nf-κb Pathway In Piglets

The objective of this study was to determine the regulatory effect of arginine (Arg) on the injury of intestinal barrier function induced by Escherichia coli lipopolysaccharide (LPS) in weaned pigs and its mechanism. A total of eighteen crossed-bred piglets (Duroc×Landrace×Yorkshine) were randomly allotted to one of three treatments (6 replicates /treatment and 1 pig/replicate) including: (1) basal diet (control group); (2) basal diet + LPS-challenged (LPS group); (3) basal diet + LPS-challenged + 0.5% arginine (0.5% Arg group). On d 18 of the trial, pigs in the LPS and 0.5% Arg groups were injected intraperitoneally with 100μg/kg BW LPS, whereas pigs in the control group were injected with an equivalent amount of sterile saline. Blood samples were collected 4 h after LPS challenge. Subsequently, the pigs were slaughtered to collect intestinal mucosa for analysis. The results showed that: (1) LPS challenge led to intestinal villus failed off and autolysis seriously, and mucosal structure damaged badly. 0.5%Arg alleviated LPS-induced villus failed off and autolysis, and improved villus morphology and structure greatly; (2) Compared with control, LPS challenge decreased diamino oxidase (DAO) activity of duodenum mucosa (P<0.05), but had no effect on plasma level of D-lactate (P﹥0.05). 0.5%Arg increased DAO activity of duodenum and ileum mucosa, and decreased plasma level of D-lactate compared with LPS group (P<0.05); (3) LPS challenge increased tumor necrosis factor-α(TNF-α) and endothelin-1 (ET-1) content of duodenum and jejunum mucosa (P<0.05). 0.5%Arg alleviated LPS-induced the increases of ET-1 content in duodenum mucosa and TNF-αcontent in jejunum and ileum mucosa (P<0.05); (4) LPS challenge increased catalase (CAT) activity of duodenum mucosa, glutathione peroxidase (GSH-px) activity and the GSH content and GSH:GSSG ratio of jejunum mucosa, and the malondialdehyde (MDA) content of ileum mucosa (P<0.05). Compared with LPS group, 0.5%Arg decreased CAT activity of duodenum and ileum mucosa, the GSH-PX activity of jejunum and ileum mucosa, the MDA content of ileum mucosa, and the GSH content of jejunum mucosa (P<0.05); (5) Compared with control, LPS challenge decreased peroxisome proliferator-activated receptor-γ(PPARγ) expression of duodenum and jejunum mucosa, meanwhile increased nuclear factor-κB (NF-κB) expression of duodenum mucosa (P<0.05). 0.5%Arg increased PPARγexpression of duodenum mucosa and decreased NF-κB expression of duodenum, jejunum and ileum mucosa. These results suggest that 0.5%Arg alleviated intestinal mucosal barrier function damage induced by LPS challenge. Maybe, the protective effects of Arg were contributed to inhibiting the production of inflammatory cytokines, free radicals and ET-1 through activating PPAR_γand inhibiting NF-κB.