Rapid and prolonged impairment of gut barrier function after thermal injury in mice

Loss of gut barrier function after burn injury can be important in the pathogenesis of systemic infections and organ dysfunction. The purpose of this study was to determine how rapidly impairment of gut barrier function occurs after burn injury and how long it persists. BALB/c mice were gavaged with 10¹⁰¹¹¹In-oxine-labeled Escherichia coli 3 h before inflicting a 20% total body surface area burn. They were then killed at 5, 15, 30, 60, 120, or 240 min post-burn. Additional mice were given a 20% or 30% burn injury and were randomized into eight groups, which were killed at either 4 h or 1, 2, 4, 7, 14, or 21 days post-burn. Each mouse was gavaged with 10^{10 111}In-oxine-labeled E. coli 4 h before sacrifice to determine the magnitude of translocation. Gut barrier function was impaired as early as 5 min post-burn and was maximal by 4 h. Rapid improvement was observed by 24 h, followed by slow improvement, but with persistent abnormality through 21 days post-burn. Killing of translocated bacteria was impaired at 4 h and day 7 post-burn, according to the percentage of viable E. coli that remained alive in the tissues. The magnitude of gut dysfunction following burn injury is temporally related.