Simulated altitude exercise training damages small intestinal mucosa barrier in the rats

Abstract

This study investigated the effect of simulated altitude training on the changes of small intestinal mucosa barrier, bacterial overgrowth and inflammatory response in the small intestine of rat. Male 8-week-old Sprague-Dawley rats were randomly divided into four groups: normal oxygen sedentary group (n=30), normal oxygen exercise group (n=30), low oxygen sedentary group (n=30) and low oxygen exercise group (n=30). Exercise training was on a treadmill for 1 hr per day on days 3, 6, and 9 in the hypoxia condition. Hematological profiles, hematolxylin and eosin staining, fluorescence in situ hybridization, reverse transcrip-tion-polymerase chain reaction and Western blot were used to analyze the effect of simulated altitude training on the amount of bacteria, and expression of mRNA and protein. Simulated exercise training signifi-cantly increased red blood cells and hematocrit. The small intestinal mucosa barrier was significantly injured by the simulated altitude exer-cise training. Comparatively more bacterial growth was evident in the small intestine by the simulated altitude exercise training. mRNA levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) and pro-tein expression of nuclear factor-kappa B (NF-κB) were significantly el-evated by simulated altitude exercise training. These results suggest that the simulated altitude exercise training may impair the small intes-tinal mucosa barrier via elevation of bacterial growth and inflammatory cytokines (IL-6, TNF-α) and the up-regulation of NF-κB in the rats.