Implication of gut microbiota in the physiology of rats intermittently exposed to cold and hypobaric hypoxia.

Sara Ramos-Romero,Susana Amézqueta,Josep Lluís Torres,Teresa Pagés,Carles Rosés,Joan Ramon Torrella,Garoa Santocildes,Mercè Hereu,David Piñol-Piñol,Ginés Viscor,François Blachier

doi:10.1371/journal.pone.0240686

Abstract

This study examines the influence of intermittent exposure to cold, hypobaric hypoxia, and their combination, in gut microbiota and their metabolites in vivo, and explores their effects on the physiology of the host. Sprague-Dawley rats were exposed to cold (4°C), hypobaric hypoxia (462 torr), or both simultaneously, 4 h/day for 21 days. Biometrical and hematological parameters were monitored. Gut bacterial subgroups were evaluated by qPCR and short-chain fatty acids were determined by gas chromatography in caecum and feces. Cold increased brown adipose tissue, Clostridiales subpopulation and the concentration of butyric and isovaleric acids in caecum. Hypobaric hypoxia increased hemoglobin, red and white cell counts and Enterobacteriales, and reduced body and adipose tissues weights and Lactobacilliales. Cold plus hypobaric hypoxia counteracted the hypoxia-induced weight loss as well as the increase in white blood cells, while reducing the Bacteroidetes:Firmicutes ratio and normalizing the populations of Enterobacteriales and Lactobacilliales. In conclusion, intermittent cold and hypobaric hypoxia exposures by themselves modified some of the main physiological variables in vivo, while their combination kept the rats nearer to their basal status. The reduction of the Bacteroidetes:Firmicutes ratio and balanced populations of Enterobacteriales and Lactobacilliales in the gut may contribute to this effect.

Highlights

Host health depends largely on the symbiotic benefits contributed by its microbiota
The IHH group significantly (P < 0.05) reduced their perigonadal adipose tissue (PAT) and BAT weights with respect to the control animals (CTL) group (Fig 1C & 1D), while the cold exposed (COLD) group significantly increased (P < 0.05) the weight of their BAT
The gut microbiota co-develops with the host, and its bacterial proportions are modified by his physiology and the actions of different diets and extrinsic stressors [4]

Summary

Introduction

Host health depends largely on the symbiotic benefits contributed by its microbiota. Gut microbiota is a complex microbial community mainly composed of anaerobic bacteria [1]. The host’s gut offers an ecological niche to bacterial subgroups, which in turn, provide nutrients and energy to the host through the degradation of dietary polysaccharides. The composition of gut microbiota originally depends on the mode of delivery, maternal microbiota, hygiene of the neonatal environment, use of antibiotic, breast milk or formula regime, and the weaning diet [2].

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