Dictyophora polysaccharides alleviate intestinal-hepatic injury exposed to low-arsenic by regulating the imbalance of gut microbiota and LPS/TLR4 pathway in rats

Abstract

Intestinal and liver damage caused by low arsenic exposure exists in worldwide, but the pathogenic mechanism is not clear at present.Dictyophora is a characteristic edible and medicinal fungus in China, and research has shown that its polysaccharides have good prebiotic effects.Therefore,we explored whether volva polysaccharide from Dictyophora has a certain therapeutic effect and its mechanism on intestinal and hepatic injury caused by low arsenic exposure.Firstly,we constructed the SD rat model of enteritis caused by low arsenic-induced.Then, from the perspectives of inflammatory responses capacity,histological alterations and serum biochemical levels of rats by arsenic-exposed with DIP intervention are analyzes the possible mechanism of intestinal and liver injury.Besides, the caecal microbiomes patterns were analysed using 16 S rDNA amplicon sequencing.Results showed that dictyophora polysaccharide increased the abundance of beneficial bacteria such as Turicibacter, Oscillospiraceae_UCG-005,and reduced the abundance of Desulfovibrionia and Lachnospiraceae_NK4A136_group proinflammatory bacteria.After dictyophora polysaccharide intervention, the pathological changes of liver and colon were alleviated,and the levels of triglyceride, total cholesterol,and lipopolysaccharide in hepatic portal vein, total arsenic contents in the liver and colon tissues were reduced. Finally,we also found after dictyophora polysaccharide intervention,the gene and protein expression of Toll-like receptor 4 was returned to normal level,and the expression levels of pro-inflammatory factors in liver and colon were reduce. In summary, our study found that dictyophora polysaccharide alleviated intestinal and hepatic injury in rats exposed to low arsenic by regulated intestinal microbiota and reduced TLR4 activation, which inhibited downstream proteins MyD88 to reduce the nuclear translocation of the NF-κB p65 genes and protein.