Exercise induction of gut microbiota modifications in obese, non-obese and hypertensive rats

Abstract

Background: Obesity is a multifactor disease associated with cardiovascular disorders such as hypertension. Recently, gut microbiota was linked to obesity pathogenesisand shown to influence the host metabolism. Moreover, several factors such as host-genotype and life-style have been shown to modulate gut microbiota composition. Exercise is a well-known agent used for the treatment of numerous pathologies, such as obesity and hypertension; it has recently been demonstrated to shape gut microbiota consortia. Since exercise-altered microbiota could possibly improve the treatment of diseases related to dysfunctional microbiota, this study aimed to examine the effect of controlled exercise training on gut microbial composition in Obese rats (n = 3), non-obese Wistar rats (n = 3) and Spontaneously Hypertensive rats (n = 3). Pyrosequencing of 16S rRNA genes from fecal samples collected before and after exercise training was used for this purpose.

Results: Exercise altered the composition and diversity of gut bacteria at genus level in all rat lineages. Allobaculum (Hypertensive rats), Pseudomonas and Lactobacillus (Obese rats) were shown to be enriched after exercise, while Streptococcus (Wistar rats), Aggregatibacter and Sutturella (Hypertensive rats) were more enhanced before exercise. A significant correlation was seen in the Clostridiaceae and Bacteroidaceae families and Oscillospira and Ruminococcus genera with blood lactate accumulation. Moreover, Wistar and Hypertensive rats were shown to share a similar microbiota composition, as opposed to Obese rats. Finally, Streptococcus alactolyticus, Bifidobacterium animalis, Ruminococcus gnavus, Aggregatibacter pneumotropica and Bifidobacterium pseudolongum were enriched in Obese rats.

Conclusions: These data indicate that non-obese and hypertensive rats harbor a different gut microbiota from obese rats and that exercise training alters gut microbiota from an obese and hypertensive genotype background.

Figure 1

Training parameters. Comparison between exercise training velocity from MLSS (vMLSS) before and after four weeks of treadmill running exercise at moderate intensity, indicating that all animals from each group enhanced their aerobic capacity as demonstrated by improvement in the MLSS corresponding to velocity (15 m.min⁻¹ for Obese rats and 3 0 m.min⁻¹ for Hypertensive and Wistar rats) (A). When the initial and final velocity of exercise training was compared, a significant reduction was evidenced in BLC of ~49% for Wistar rats, ~39% for Hypertensive rats and ~33% for Obese rats (p < 0.01) (B).

Figure 2

Effect of exercise on Genus relative abundance. Proportion of relative abundance for the statistical analyses of Genus level profiles distributed in Wistar rats (A), Hypertensive rats (B) and Obese rats (C). The genera were altered between without exercise training (white bar) and with exercise training (black bar). Features with a α-value of < 0.05 were considered significant.

Figure 3

Species abundance profile of fecal sample before and after exercise training. Box plot showing the distribution in the proportion of sequences (%) of main species of each rat lineage (A; Bacteroides acidifaciens, B; Ruminococcus flavefaciens, C ; Streptococcus alactolyticus, D; Bifidobacterium animalis, E; Ruminococcus gnavus, F; Aggregatibacter pneumotropica, G; Bifidobacterium pseudolongum) without exercise training (white box) and with exercise training (black box). The median value is shown as a line within the box and the mean value as a star, p-value for statistical significance was defined as p ≤ 0.05.

Figure 4

Effect of exercise training on bacterial community. Principal coordinates analysis (PCoA) of unweighted UniFrac distances generated from fecal samples in Wistar rats (squares), Hypertensive rats (circles) and Obese rats (diamonds) collected from triplicate rats without exercise training (white symbols) and with exercise training (black symbols). The result of the ANOSIM similarity analyses confirmed that samples harbor a distinct bacterial community.

Figure 5

Microbial abundance and blood lactate concentration correlation. Correlations between the relative abundances of the bacterial communities (OTUs) and blood lactate concentration (mmol.L⁻¹). Gut microbiota profile was determined by 16S rRNA pyrosequencing for Wistar rats, Hypertensive rats and Obese rats in fecal samples. Pearson correlation coefficients (r) are shown for each taxon (A; Clostridiaceae, B; Bacteroidaceae, C; Oscillospira, D; Ruminococcus), with the associated FDR-corrected P values.