Experimental acute pancreatitis results in increased blood-brain barrier permeability in the rat: a potential role for tumor necrosis factor and interleukin 6.

Pancreatic encephalopathy is a severe complication of acute pancreatitis. Proinflammatory cytokines may play a role in the development of multi-organ failure during pancreatitis. In the present study, we measured the changes in the blood-brain barrier (BBB) permeability concomitantly with the determination of serum tumor necrosis factor (TNF) and interleukin-6 (IL-6) levels in rats before, as well as 6, 24 and 48 h after the beginning of intraductal taurocholic acid-induced acute pancreatitis. Cytokine concentrations were measured in bioassays with specific cell lines (WEHI-164 for TNF and B-9 for IL-6), while the BBB permeability was determined for a small (sodium fluorescein, molecular weight (MW) 376 Da), and a large (Evans' blue-albumin, MW 67000 Da) tracer by spectrophotometry in the parietal cortex, hippocampus, striatum, cerebellum and medulla of rats. The serum TNF level was significantly (P < 0.05) increased 6 and 24 h after the induction of pancreatitis, while the IL-6 level increased after 24 and 48 h. A significant (P < 0.05) increase in BBB permeability for both tracers developed at 6 and 24 h in different brain regions of animals with acute pancreatitis. We conclude that cytokines, such as TNF and IL-6, may contribute to the vasogenic brain edema formation during acute pancreatitis.