Effects of dexamethasone on intercellular adhesion molecule 1 expression and inflammatory response in necrotizing acute pancreatitis in rats.

Objectives: Adhesion molecules are involved in the inflammatory response during acute pancreatitis (AP). We investigated the effect of dexamethasone (Dx) on intercellular adhesion molecule 1 (ICAM-1) expression during AP and its consequences on leukocyte recruitment and pancreatic damage.

Methods: Acute pancreatitis was induced in rats by 3.5% sodium taurocholate for 3 hours and 6 hours. Dexamethasone (1 mg/kg) was administered either 30 minutes before or 1 hour after inducing AP. Messenger RNA ICAM-1 expression in pancreas and lung, membrane-bound ICAM-1 in acinar cells, and ICAM-1 plasma levels were analyzed. Histological examination of the pancreas and neutrophil infiltration in pancreas and lung were also measured.

Results: Prophylactic and therapeutic administration of Dx down-regulated ICAM-1 expression in pancreas and lung from early AP. Dexamethasone given before AP reduced the pancreatic damage, but lung inflammation was not prevented. Therapeutic Dx treatment was ineffective in avoiding leukocyte recruitment into the pancreas and lung in rats with AP. High ICAM-1 concentration was found in plasma during AP, which was not reduced by Dx treatments.

Conclusions: Dexamethasone down-regulates ICAM-1 expression, but it does not completely prevent leukocyte recruitment during sodium taurocholate-induced AP.