| Since the 21st century,many researches have shown that most chronic non-communicable diseases such as chronic obstructive pulmonary disease,diabetes,and cancer are inextricably linked to chronic inflammation,which has seriously affected human life and health.Houttuynia cordata has always been called"antibiotic of traditional Chinese medicine",and is an important medicinal/dietary resource.Houttuynia cordata polysaccharide(HCP)is one of its main active ingredients,and its antibacterial,immunomodulatory and anti-inflammatory active functions have become the focus nowdays.Previous studies have reported that HCP has a good anti-inflammatory effect on acute inflammation,and there are few reports about the effect of HCP on chronic inflammation.Therefore,this study used water extraction and alcohol precipitation method to extract HCP and determine its basic physical and chemical properties,and established chronic inflammation rat model by injecting lipopolysaccharide(LPS)into tail vein,to explore the effect of HCP on chronic inflammation from three aspects of overall anti-inflammatory,lung protection and intestinal protection.The main research contents and results are summarized as follows:1.The yield of HCP was 2.79%and its physical and chemical experiments showed that the neutral sugar content was 40.51%,the uronic acid content was 51.11%,and the protein content was 3.16%.Spectroscopic analysis showed that HCP may be an acid polysaccharide and containing pyran ring structure.Chromatography showed that the weight-average relative molecular weight of HCP was 3.87×105 Da and the main monosaccharides are galacturonic acid,galactose and glucose.Scanning electron microscopy observation revealed that HCP consisted of rod-shaped,filamentous and spherical materials.In vitro antioxidant experiments found that the removal efficiency of HCP to DPPH and OH free radicals can reach 87.18%and 31.37%,respectively.2.The effect of HCP on the body weight of rats is not very obvious in the experimental period,but it can significantly increase the index of heart organ and decrease the index of thymus and spleen in chronic inflammatory rats.HCP can alleviate the inflammatory pathological damage of liver and maintain the normal structure of liver tissue.In addition,HCP can reduce VBC,monocyte number and serum hs-CRP content,and improve the antioxidant capacity of liver tissue in chronic inflammatory rats.The results showed that HCP has a effective overall anti-inflammatory effect on LPS-induced chronic inflammation in rats.3.HCP can maintain the normal structure and morphology of lung tissue,reduce the infiltration of inflammatory cells,and relieve the pathological damage of lung in chronic inflammatory rats and can significantly inhibit the up-regulation of TLR4,NF-KBp65 and p62 protein expression in the lung.Subsequently,HCP can improve the antioxidant capacity of lung tissue,and significantly reduce the levels of NO,iNOS and tNOS and inflammatory cytokines IL-1?,IL-6 and TNF-? in the lung of chronic inflammatory rats.The results showed that HCP may ameliorate the inflammatory damage through the TLR4/NF-?B signal transduction pathway and have a protective effect on the lung of chronic inflammatory rats.4.HCP can promote the arrangement of intestinal villi,reduce the swelling degree of intestinal villi,alleviate the inflammatory damage of intestinal tissue and can increase the expression of ZO-1 protein of small intestine in chronic inflammatory rats.Secondly,HCP can improve the anti oxidant ability and reduce the content of inflammatory mediators NO,iNOS,tNOS and inflammatory cytokine IL-1? of small intestine in chronic inflammatory rats.Moreover,HCP can increase the content of water and SCFAs and reduce the pH value of colonic contents.Furthermore,HCP can reduce the F/B value of gut microbiota and the relative abundance of Bacteroides,Parabacteroides and Proteus in feces.The results showed HCP can protect the intestine of chronically inflamed rats by reducing inflammatory damage of intestinal tissue and adjusting the structure of gut microbiota. |
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