[Improvement of bifidobacterial supplement on the barrier function of intestinal mucosa and microbe flora induced by thermal injury in rats].

Objective: To investigate the potential effect of bifidobacterial supplement on intestinal mucosal and biological barrier following severe burns.

Methods: Seventy Wistar rats were randomly divided into burn control group (BC, n=30), burn + treatment group (BT, n=30), and sham-burn group (NC, n=10). Animals in BT group were fed bifidobacterial preparation (5x10(12) CFU/L) after 30% total body surface area (TBSA) full-thickness thermal injury, 1.5 ml, twice daily. Samples were taken on postburn days 1,3,and 5. The incidence of bacteria/endotoxin translocation and the counts of bifidobacteria, E.coli, and fungi in ileo-cecum mucosa were determined with standard methods. Ileum mucosal injuries were evaluated light and electron microscopically by blinded examiners.

Results: (1) The incidence of bacterial translocation were 42% and 16% in BC and BT groups on postburn day 3 (P=0.004 0), 30% and 6% on day 5 (P=0.002 0), respectively. Plasma endotoxin levels were markedly higher in BC and BT groups than that in NC group at the early stage postburn, while there was a significant decrease in BT group compared with BC group on postburn day 1 (P=0.04). (2) The bifidobacteria counts in ileo-cecum mucosa were reduced by 10- to 60-fold after thermal injury, while there was a remarkable increase in animals fed with bifidobacteria. The E.coli counts in ileo -cecum mucosa were increased by 20- to 30-fold on postburn days 1 and 3, whereas those markedly reduced after 3-day bifidobacteria-supplemented formula, tending to normal range.(3)There were obviously ileum mucosal lesions on postburn days 1 and 3,the ileum lesion scores remained significant higher in B C group than that in NC group on postburn 5 day (P<0.05).However,the damage d ileum mucosa was markedly repaired after 3-day bifidobacteria-supplemented formula, and almost restored 5 days later.

Conclusion: The intestinal mucosal and biological barrier appear to be markedly damaged after severe burns. The supplement of exogenous bifidobacteria can facilitate the improvement of mucosal as well as biological barrier function, thereby reducing the incidence of bacteria/endotoxin translocation secondary to major burns.