Portulaca oleracea L. polysaccharide ameliorates lipopolysaccharide-induced inflammatory responses and barrier dysfunction in porcine intestinal epithelial monolayers
Shen Zhuang, Ke Ming, Ning Ma, Jinrui Sun, Dehai Wang, Mingxing Ding, Yi Ding
Abstract
Intestinal epithelial barrier and inflammatory responses are common pathological process in intestinal diseases. Effects of a specific polysaccharide fraction (POPZ) from Portulaca oleracea L. on LPS-induced barrier injury and inflammatory responses were studied in porcine intestinal epithelial monolayer. POPZ was characterized by its molecular constituents with Man, GlcUA, Glc, Gal, Xyl and Fuc (0.247:0.245: 0.225: 0.179: 0.077:0.026, molar ratio), and Mp (41.496 kDa), Mw (51.418 kDa) and Mn (34.455 kDa). POPZ inhibited an increase in FD4 and phenol red permeability, and a decrease in TER and p-EGFR levels, and ZO-1, OCLN, claudin-7 and EGFR expression in LPS-treated porcine intestinal epithelial monolayer, which were counteracted by ZD1839, an EGFR inhibitor. It also ameliorated LPS-induced increase in IL-1β, IL-6, TNF-α, TLR4, NF-κB p-p65 and NF-κB p65 nuclear translocation. Taken together, POPz could relieve inflammatory responses and maintain the intestinal epithelial barrier via inactivating TLR4/NF-κB pathway and activating EGF/EGFR pathway.