Composition Of Gut Microbiota In Mice Research Articles

Limited Effects of Low-to-Moderate Aerobic Exercise on the Gut Microbiota of Mice Subjected to a High-Fat Diet.

Several studies have indicated that diet and exercise may modulate the gut microbiota in obese subjects. Both interventions were shown to alter the microbiota orthogonally. However, this relationship has not been fully explored. This study analyzed the effects of low-to-moderate aerobic training on the fecal microbiota of mice subjected to a high-fat diet (HFD). Here, 40 male mice (C57Bl/6) were divided into two groups with standard diet (SD; 12.4% lipid) and HFD (60.3% lipid) for four months. These groups were divided into four, named SD control, HF control, SD trained and HF trained. All animals were submitted to an incremental test to estimate low-to-moderate maximum speed. Training consisted of 30 min·day−1, 5 days/week, for 8 weeks. The HFD increased the body weight (p < 0.0001) and adiposity index (p < 0.05). HFD also negatively influenced performance in exercise training. Moreover, the diversity of gut microbiota was reduced by the HFD in all groups. A low-to-moderate exercise was ineffective in modulating the gut microbiota composition in mice subjected to HFD. These findings suggest that two months of low-to-moderate exercise does not achieve a preponderant modulatory effect on shaping microbiota when submitted to the high-fat diet.

Behavioral response to fiber feeding is cohort-dependent and associated with gut microbiota composition in mice

Recent data has supported a role for the gut microbiota in improving cognition and shaping behavior. Here, we assessed whether pectin, a soluble, fermentable fiber, could enhance learning and memory in mice. Two cohorts of young male C57Bl/6 J mice, C1 (n = 20) and C2 (n = 20), were obtained from Jackson Laboratory and randomized to semi-purified AIN-93 M diets containing 5% pectin (n = 10) or cellulose (n = 10). After 16 weeks, learning and memory was assessed by Morris Water Maze (MWM) and microbiota composition was analyzed by 16S rRNA sequencing. Despite identical treatment, we observed differences in learning and memory abilities between cohorts, along with distinct microbiotas. In C1, pectin-fed mice spent a higher percentage of time in the target quadrant at the 24-h probe trial of the MWM versus cellulose-fed mice; in C2, no effect of pectin was observed. In both cohorts, UniFrac distance revealed significant differences in gut microbial communities between cellulose-fed and pectin-fed mice. UniFrac analysis also revealed significantly different bacterial communities between cohorts. Further analysis demonstrated that the microbial genera Oscillospira, Bilophila, and Peptostreptococcoceae were more abundant in C1 versus C2, and positively associated with distance from the platform during the 24-h probe test. These data support previous findings that differences in the gut microbiota may play a role in host response to a dietary intervention and could partly explain irreproducibility in psychological and behavioral experiments. Further research is needed to determine if a causal relationship exists.

Oral insulin does not alter gut microbiota composition of NOD mice.

Oral insulin as a preventive strategy and/or treatment of type 1 diabetes has been the target of much research. Producing oral insulins is a complex and challenging task, with numerous pitfalls, due to physiological, physical, and biochemical barriers. Our aim was to determine the impact of oral insulin on the delicate gut microbiota composition. Female nonobese diabetic mice were given oral porcine insulin 2 times a week from 5weeks of age for 4weeks, and then subsequently once a week for 21weeks, or until euthanized. The mice were divided into groups on a gluten-reduced diet or a standard diet. Gut microbiota composition was analysed based on faecal samples, and the type 1 diabetes incidence of the mice was monitored. We observed no influence of the oral porcine insulin on the gut microbiota composition of mice on a gluten-reduced or a standard diet at 9weeks of age. Also, the administration of oral insulin did not influence the incidence of type 1 diabetes at 30weeks of age. Oral porcine insulin does not alter the gut microbiota composition of nonobese diabetic mice on either a gluten-reduced diet or standard diet. Also, the oral porcine insulin did not influence the incidence of type 1 diabetes in the groups.

Exposure to Formaldehyde Perturbs the Mouse Gut Microbiome.

Exposure to Formaldehyde (FA) results in many pathophysiological symptoms, however the underlying mechanisms are not well understood. Given the complicated modulatory role of intestinal microbiota on human health, we hypothesized that interactions between FA and the gut microbiome may account for FA’s toxicity. Balb/c mice were allocated randomly to three groups: a control group, a methanol group (0.1 and 0.3 ng/mL MeOH subgroups), and an FA group (1 and 3 ng/mL FA subgroups). Groups of either three or six mice were used for the control or experiment. We applied high-throughput sequencing of 16S ribosomal RNA (rRNA) gene approaches and investigated possible alterations in the composition of mouse gut microbiota induced by FA. Changes in bacterial genera induced by FA exposure were identified. By analyzing KEGG metabolic pathways predicted by PICRUSt software, we also explored the potential metabolic changes, such as alpha-Linolenic acid metabolism and pathways in cancer, associated with FA exposure in mice. To the best of our knowledge, this preliminary study is the first to identify changes in the mouse gut microbiome after FA exposure, and to analyze the relevant potential metabolisms. The limitation of this study: this study is relatively small and needs to be further confirmed through a larger study.

Ganoderma lucidum polysaccharides improve insulin sensitivity by regulating inflammatory cytokines and gut microbiota composition in mice

Ectopic lipid accumulation and low-grade chronic inflammation are critical pathogenesis of insulin resistance development. Ganoderma lucidum is a traditional Chinese herb for balancing energy homeostasis. In this research, we determined the effects of G. lucidum polysaccharides (GLP) on high-fat diet (HFD)-induced insulin resistant mice. We observed that GLP treatment decreased plasma insulin concentration and reversed HFD-induced systemic insulin resistance. Meanwhile, GLP ameliorated low-grade chronic inflammation, inducing lipolysis in adipose tissues. GLP decreased plasma triglyceride and non-esterified fatty acid outflux by suppressing mRNA expressions of hormone-sensitive lipase, fatty acid binding protein 4, tumor necrosis factor-α, and interleukin-6 in epididymal fat. Finally, GLP treatment suppressed ectopic lipid accumulation in peripheral tissues and hepatic insulin-regulated lipogenesis. GLP also regulated composition of gut microbiota implicated in type 2 diabetes mellitus development.

Repeated Oral Exposure to N ε-Carboxymethyllysine, a Maillard Reaction Product, Alleviates Gut Microbiota Dysbiosis in Colitic Mice.

Diet is suggested to participate in the etiology of inflammatory bowel diseases (IBD). Repeated exposure to Maillard reaction products (MRPs), molecules resulting from reduction reactions between amino acids and sugars during food heating, has been reported to be either potentially detrimental or beneficial to health. The aim of this study is to determine the effect of repeated oral ingestion of N ε-carboxymethyllysine (CML), an advanced MRP, on the onset of two models of experimental IBD and on the gut microbiota composition of mice. Mice received either saline (control) or N ε-carboxymethyllysine daily for 21days. For the last week of treatment, each group was split into subgroups, receiving dextran sulfate sodium salt (DSS) or trinitrobenzenesulfonic acid (TNBS) to induce colitis. Intensity of inflammation was quantified, and cecal microbiota characterized by bacterial 16S ribosomal RNA (rRNA) amplicon sequencing. Daily oral administration of N ε-carboxymethyllysine did not induce intestinal inflammation and had limited impact on gut microbiota composition (Bacteroidaceae increase, Lachnospiraceae decrease). DSS and TNBS administration resulted in expected moderate experimental colitis with a shift of Bacteroidetes/Firmicutes ratio and a significant Proteobacteria increase but with distinct profiles: different Proteobacteria taxa for DSS, but mainly Enterobacteriaceae for TNBS. While N ε-carboxymethyllysine exposure failed to prevent the inflammatory response, it allowed maintenance of healthy gut microbiota profiles in mice treated with DSS (but not TNBS). Repeated oral exposure to CML limits dysbiosis in experimental colitis. IBD patients may modulate their microbiota profile by regulating the level and type of dietary MRP consumption.

Sex differences and hormonal effects on gut microbiota composition in mice

ABSTRACTWe previously reported quantitation of gut microbiota in a panel of 89 different inbred strains of mice, and we now examine the question of sex differences in microbiota composition. When the total population of 689 mice was examined together, several taxa exhibited significant differences in abundance between sexes but a larger number of differences were observed at the single strain level, suggesting that sex differences can be obscured by host genetics and environmental factors. We also examined a subset of mice on chow and high fat diets and observed sex-by-diet interactions. We further investigated the sex differences using gonadectomized and hormone treated mice from 3 different inbred strains. Principal coordinate analysis with unweighted UniFrac distances revealed very clear effects of gonadectomy and hormone replacement on microbiota composition in all 3 strains. Moreover, bile acid analyses showed gender-specific differences as well as effects of gonodectomy, providing one possible mechanism mediating sex differences in microbiota composition.

The Rhizome Mixture of Anemarrhena asphodeloides and Coptis chinensis Attenuates Mesalazine-Resistant Colitis in Mice.

We investigated the effect of DWac on the gut microbiota composition in mice with 2,3,6-trinitrobenzenesulfonic acid- (TNBS-) induced colitis. Treatment with DWac restored TNBS-disturbed gut microbiota composition and attenuated TNBS-induced colitis. Moreover, we examined the effect of DWac in mice with mesalazine-resistant colitis (MRC). Intrarectal injection of TNBS in MRC mice caused severe colitis, as well as colon shortening, edema, and increased myeloperoxidase activity. Treatment with mesalazine (30 mg/kg) did not attenuate TNBS-induced colitis in MRC mice, whereas treatment with DWac (30 mg/kg) significantly attenuated TNBS-induced colitis. Moreover, treatment with the mixture of mesalazine (15 mg/kg) and DWac (15 mg/kg) additively attenuated colitis in MRC mice. Treatment with DWac and its mixture with mesalazine inhibited TNBS-induced activation of NF-κB and expression of M1 macrophage markers but increased TNBS-suppressed expression of M2 macrophage markers. Furthermore, these inhibited TNBS-induced T-bet, RORγt, TNF-α, and IL-17 expression but increased TNBS-suppressed Foxp3 and IL-10 expression. However, Th2 cell differentiation and GATA3 and IL-5 expression were not affected. These findings suggest that DWac can ameliorate MRC by increasing the polarization of M2 macrophage and correcting the disturbance of gut microbiota and Th1/Th17/Treg, as well as additively attenuating MRC along with mesalazine.

Dietary Phaseolus vulgaris extract alleviated diet-induced obesity, insulin resistance and hepatic steatosis and alters gut microbiota composition in mice

Phaseolus vulgaris may reduce appetite, body weight and gut microbiota and has been shown to contribute to the development of obesity, type 2 diabetes and non-alcoholic fatty liver disease. This study was conducted to investigate the impact of P. vulgaris extract (PVE) on obesity and obesity-associated metabolic syndromes, and determine whether the protective effects of PVE were associated with modulation of gut microbiota. C57BL/6J mice were fed low-fat diet, high-fat diet or high-fat diet supplemented with PVE of 50 mg/kg. The composition of gut microbiota was analysed by 16S rDNA sequencing. Our results showed that PVE treatment reduced body weight and improved hepatic steatosis and insulin resistance in high-fat diet-fed mice. PVE administration increased the relative abundance of Bifidobacterium, Lactobacillus and Akkermansia at the genus level. In conclusion, PVE protects from diet-induced obesity, insulin resistance and hepatic steatosis, and these beneficial effects were associated with the PVE-related modulation of gut microbiota.

Crosstalk Between The Immune Receptors and Gut Microbiota.

The mucosal surfaces of the intestinal tract are constantly exposed to complex microbial communities that contain commensal microorganisms and potential pathogens. Therefore, hosts harbor multiple molecular mechanisms to modulate the gut innate immunity to achieve gut-microbe homeostasis. Pattern recognition receptors (PRRs), such as Toll-like receptor (TLR) and nucleotide oligomerization domain (NOD)-like receptor (NLR), play a key role in sensing pathogens and promoting the induction of innate effectors. Gut microbiota, through PRRs, can modulate the expression of genes involved in inflammatory responses and the production of antimicrobial peptides. In turn, the expression of PRRs affects the structure of gut microbiota in health or disease status. Deficiency in PRRs such as NOD2 and TLR5 can alter the gut microbiota composition in mice. The crosstalk between PRRs and microbiota connects the microbial action with the host response. This article outlines recent advances in the role of immune sensors in the gut microbiota balance and the related microbiota-host interaction.

Microbiome/Metabolic Syndrome/Diabetes and CVD

We have carried out taxonomic profiling of gut microbiota in a population of about 100 commercially available inbred strains of mice termed the Hybrid Mouse Diversity Panel (HMDP). This panel has been developed as a systems genetics resource and can be used for high resolution association mapping of complex traits. When maintained under controlled environmental conditions, the gut microbiota composition exhibits high heritability in the HMDP as calculated using a linear mixed model assuming additive genetic effects. Genome‐wide association analysis with informative SNPs identified significant loci in the mouse genome associated with relative abundances of specific taxa. The HMDP mice have been typed for a number of cardiovascular, metabolic, and other clinical traits, allowing correlation analysis of gut microbiota composition with clinical traits. Some of these associations, such as the association between Akkermansia muciniphila levels and high fat diet response, have subsequently been confirmed in published experimental studies. A number of novel associations are presently being tested using co‐fostering of different inbred strains or experimental introduction of cultured bacterial species. A variety of diets have been studied across the HMDP. In conclusion, studies of natural variations in gut microbiota composition in mice may help identify regulatory host factors as well as providing a global view of the relationships between microbiota and clinically relevant traits.

Long‐Time Saturation Exposure Changes Gut Microbiota Composition And Intestinal Antimicrobial Defense In Mice

PURPOSELong‐time saturation exposure may induce anxiety, loss of appetite, and digestive disorders, which relate to impairment of intestinal mucosal immune system and gut microbiota homeostasis. Our study examined the effects of 4‐day of saturation exposure on gut microbiota and intestinal antimicrobial peptides (AMPs) in mice.METHOD20 male C57 Mice, 8‐week old, were randomly divided into saturation exposure group (SE, n=10) and control group (CON, n=10). SE exposed to N2/O2 mixed gas at 500kPa for 4 days in pressure chamber. Intestines were excised and stained with HE and AB‐PAS. Feces and Intestines were collected and extract gDNA and RNA respectively. We used qPCR to assay bacterial population (Bacteroides, Clostridia, Lactobacilli, Enterobacteria, and Akkermansia muciniphila) of the feces, and the AMPs (Defα5/β1, Retnlβ, Reg3β/γ) of small intestine and colon.RESULTSWithin 4 days, SE mice did not exhibit nitrogen narcosis behavior. By comparing with the 16S rRNA genes, results revealed a significant increase in the relative abundances of A. muciniphila (9.28±5.67) and Clostridia (3.45±0.63) in SE. The relative abundance of Lactobacilli was lower (0.40±0.24) in SE. Moreover, a distinct increase of Enterobacteria (23.34±8.88) was observed in SE compared with CON. Gene expressions for Defα5/β1 in SE were decreased in small intestine, while Defβ1 and Reg3γ in SE were significantly decreased, and Defα5 and Reg3β increased in colon.CONCLUSIONIn sum, the data showed that a four‐day saturation exposure induced changes in the mRNA level of AMPs, and the gut microbiota composition in mice.Found: NSFC 31471135