Dietary Supplement of Anoectochilus Roxburghii Polysaccharides Ameliorates Cognitive Dysfunction Induced by High Fat Diet via “Gut-Brain” Axis

Abstract

Background：Anoectochilus roxburghii, a traditional Chinese herbal medicine, has been widely used for treating numerous metabolic diseases. Anoectochilus roxburghii polysaccharide (ARPs) is an important constituent of Anoectochilus roxburghii. This study tried to investigate whether ARPs could improve cognitive dysfunction in diet-induced obesity.Methods: C57BL/6J male mice were randomly divided into the normal chow diet group (CD), the high-fat diet group (HFD) and HFD supplemented with ARPs (HARPs). Morris water maze test and Y maze test were used to evaluate spatial learning and memory. Serum TNF-α and LPS concentrations were detected by ELISA. Genes involved in Neurotrophic factors, inflammation and Intestinal permeability were detected by RT-PCR. Immunohistochemistry was used to detect TNF-α and ZO-1 proteins. BDNF in hippocampus was detected by immunofluorescence staining. 16S rDNA sequencing was used to detect intestinal microbial diversity.Results: Dietary supplement of ARPs ameliorates cognitive dysfunction induced by HFD. Compared with HFD mice, body weight, plasma glucose, total cholesterol and triglyceride levels in HARPs group were decreased significantly. Moreover, the cognitive function and memory of HFD mice were decreased, while ARPs abolished these effects. In addition, Tau protein levels were decreased and BDNF increased significantly in hippocampus from HARPs mice. Furthermore, compared with HFD group, IL-6 and TNF-α levels in hippocampus and colon from HARPs mice were decreased. Moreover, ARPs increased the tight junction protein levels and intestinal microbiota diversity significantly.Conclusions: Diet supplemented with ARPs prevented mice from HFD-induced cognitive dysfunction, indicated that ARPs has a good effect on obesity-related neuropathy. Mechanically, these effects at least in part attribute to the “gut-brain” axis regulation, and which can provide reference for the development of ARPs as functional foods in the future.