Expression of tight junction protein occludin in the brain microvascular endothelial cells of rats with acute necrotizing pancreatitis

Abstract

Objective To explore the changes of expression of tight junction protein occludin in the brain microvascular endothelial cells of rats with acute necrotizing pancreatitis (ANP), and to study the relationship between the occludin expression and degree of pancreatic pathologic changes. Methods 80 rats were randomly divided into sham-operation (SO) group and ANP 3 h, 6 h, 12 h, and 24 h groups. Retrograde pancreatic duct injection of 5% choleate sodium in rats was used to establish ANP models. Pancreatic pathologic changes was evaluated. Immunohistochemistry, Western blot and RT-PCR were used to determine the expressions of the tight junction protein occludin in the brain microvascular endothelial cells. Results Occludin protein was linearly expressed along brain vascular vessels. The expression of occludin protein at 3h was 0. 35±0.09 in brain tissues from rats with ANP and 0. 49±0.08 in SO group, the expression of occludin mRNA were decreased from 1.50±0.30 to 1.01±0.18 (P < 0.05), the lowest expression rate occurred at 6 h, and the values in the two groups were 0. 26±0.07 and 0. 93±0. 19, respectively, the expressions of occludin protein and mRNA of ANP group at 12 h, 24 h were notably increased when compared with those at 6 h (P < 0. 05), but they were still lower than those in SO group (P < 0.05). The occludin protein and mRNA expressions were negatively related with the degree of pancreatic pathologic changes (Pearson correlation coefficient: -0.48 and -0.536, P < 0.05). Conclusions The expression of tight junction protein occludin decreased at both protein and mRNA level in brain microvascular endothelial cells of ANP rats. Furthermore, the expression of occludin was negatively correlated with pathological change of pancreas. Key words: Pancreatitis, acute necrotizing;  Blood-brain barrier;  Connexins;  Occludin