Nitric oxide synthase inhibition reduces albumin induced lung damage in acute pancreatitis

Abstract Background/objectives Colloid resuscitation in acute pancreatitis (AP) is a matter of controversy due to the possible deleterious effect on lung function. A previous study demonstrates that albumin administration increases lung damage in burns and this effect can be reversed by inducible nitric oxide synthase (iNOS) inhibition. This study evaluates the effects of S-methylisothiourea (SMT), a specific iNOS inhibitor, on lungs and pancreas of rats with AP receiving intravenous albumin. Methods AP was induced in Wistar rats by intraductal 5% taurocholate injection. To evaluate the effect of albumin on lung damage, animals received IV saline or human albumin immediately after AP (Groups: Saline and Albumin). To evaluate the effect of iNOS inhibition on lung damage, SMT was given immediately after AP (Group Saline+SMT, and Group Albumin+SMT). At 12 h after AP induction, serum amylase activity, lung vascular permeability and myeloperoxidase (MPO) activity were evaluated. Lung and pancreas histological analysis were performed. Results Serum amylase activity, pancreatic edema, lung vascular permeability, MPO activity, and inflammatory infiltration were significantly increased after AP. Albumin administration increased lung vascular permeability, inflammatory infiltration, and pancreatic edema compared to saline administration ( p