Nopal (Opuntia ficus indica) protects from metabolic endotoxemia by modifying gut microbiota in obese rats fed high fat/sucrose diet

Mónica Sánchez-Tapia,Sharon M Donovan,Mei Wang,Edgar Pichardo-Ontiveros,Miriam Aguilar-López,Nimbe Torres,Armando R Tovar,Claudia Pérez-Cruz

doi:10.1038/s41598-017-05096-4

Abstract

Current efforts are directed to reducing the gut dysbiosis and inflammation produced by obesity. The purpose of this study was to investigate whether consuming nopal, a vegetable rich in dietary fibre, vitamin C, and polyphenols can reduce the metabolic consequences of obesity by modifying the gut microbiota and preventing metabolic endotoxemia in rats fed a high fat and sucrose diet. With this aim, rats were fed a high fat diet with 5% sucrose in the drinking water (HFS) for 7 months and then were fed for 1 month with HFS + 5% nopal (HFS + N). The composition of gut microbiota was assessed by sequencing the 16S rRNA gene. Nopal modified gut microbiota and increased intestinal occludin-1 in the HFS + N group. This was associated with a decrease in metabolic endotoxemia, glucose insulinotropic peptide, glucose intolerance, lipogenesis, and metabolic inflexibility. These changes were accompanied by reduced hepatic steatosis and oxidative stress in adipose tissue and brain, and improved cognitive function, associated with an increase in B. fragilis. This study supports the use of nopal as a functional food and prebiotic for its ability to modify gut microbiota and to reduce metabolic endotoxemia and other obesity-related biochemical abnormalities.

Highlights

Increased consumption of foods high in fat and sugar are the main contributors of obesity[1], gut microbiota dysbiosis[2], inflammation[3], gut barrier disruption[4] and cognitive decline[5]
We found that obese rats fed high fat-sucrose diet (HFS) + N, HFS-C + N or HFS-C significantly decreased the expression of the genes tumor necrosis factor-α (Tnf-α), and NADPH oxidase (Nox) involved in inflammation and oxidative stress in white adipose tissue with respect to the rats fed HFS diet, (Fig. 7D,E)
The results showed that the amelioration in the biochemical abnormalities of serum glucose and lipids in the HFS + N, HFS-C + N and HFS-C groups was accompanied by a reduction in the expression of genes involved in lipogenesis

Summary

Introduction

Increased consumption of foods high in fat and sugar are the main contributors of obesity[1], gut microbiota dysbiosis[2], inflammation[3], gut barrier disruption[4] and cognitive decline[5]. Evidence shows a causal link between the intestinal microbiota and insulin resistance through different mechanisms including the increase in the production of short chain fatty acids by increasing hepatic lipogenesis[6], the conversion of primary to secondary bile acids by the gut microbiota regulating the membrane-type receptor for bile acids TGR57, and by a chronic low-grade inflammation mediated by lipopolysaccharide (LPS) activating a cell signalling pathway that induces an inflammatory response and cytokine secretion. Efforts to improve insulin sensitivity have been directed to reducing dysbiosis of the gut microbiota, with one of the most effective strategies being modification of the diet to reduce insulin resistance and increase systemic and local intestinal anti-inflammatory activities[10]. We investigate whether obese rats fed with nopal can modify gut microbiota to attenuate metabolic endotoxemia and the subsequent insulin resistance, biochemical abnormalities and improve cognitive function in rats fed a sucrose-enriched high fat diet

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Conclusion