Temporal variations of the ileal microbiota in intestinal ischemia and reperfusion

Gastrointestinal bacteria and epithelia contribute to systemic inflammation and infections in critically ill patients, but the gut microbiota in these diseases has not been analyzed dynamically by molecular fingerprinting methods. This study aimed to identify ileal flora dysbiosis pattern and bacterial species that changed significantly in a rat model of intestinal ischemia and reperfusion and illustrate time courses of both epithelial alterations and gut flora variations in the same injury. Forty-eight rats were randomized into eight groups (n = 6/group). Six groups underwent superior mesenteric artery occlusion for 30 min and were killed at 1, 3, 6, 12, 24, and 72 h following reperfusion, respectively; a group of rats were killed just after anesthesia (control), and a sham-operated group received 12-h reperfusion. Denaturing gradient gel electrophoresis of ileal microbiota showed that gut flora pattern changed early after intestinal ischemia and reperfusion, differed significantly at 12 h of reperfusion, and then started to recover toward normal pattern. The specific dysbiosis were characterized by Escherichia coli proliferation and Lachnospiraceae and Lactobacilli reduction. These bacteria that contributed most were identified by principal component analysis and sequencing and confirmed by real-time polymerase chain reaction. In addition, alterations of ileal microbiota followed epithelial changes in the time course of reperfusion.