Role of neutrophils in burn-induced microvascular injury in the intestine

The present study evaluated burn-induced vascular permeability alterations of rat small intestine in vivo and assessed the effect of neutrophil deplet ion in burn-injured rats on the altered intestinal microvascular permeabili ty. I-125-labeled bovine serum albumin (I-125-BSA) was injected intravenous ly, and its leakage from circulation into the intestinal tissue was determi ned by measuring tissue counts of I-125-BSA. Compared with sham, vascular a lbumin permeability increased 1.7-fold on day 1 post-burn and 3.0-fold on d ay 3 post-burn in ileum. In the jejunum, albumin permeability increased 1.8 - and 2.5-fold on day 1 and day 3 post-burn, respectively. Intestinal tissu e edema, determined as increases in tissue water contents, was noted in bot h intestinal segments on day 1 post-burn; no further increase in edema was found on day 3 post-burn. Neutrophil depletion before burn injury prevented the vascular leakage of albumin and edema in the ileum and jejunum on day 1 post-burn. On day 3 post-burn, the effect of prior neutrophil depletion o n vascular permeability was less marked, and edema formation was not affect ed at all. These findings indicate that an absence of neutrophils prevents the loss of intestinal vascular barrier properties only in the initial peri ods after burns.