The time course of gap-junctional protein connexin 32 expression in the pancreas after the induction of acute pancreatitis by caerulein in rats

Background: Background: We previously demonstrated that the immunostaining of the gap-junction protein, connexin 32 (Cx 32), in the pancreas was markedly reduced in caerulein (Cn)-induced acute pancreatitis. The expression of Cx 32 in the pancreas during the course of acute pancreatitis is unclear. To address this, we examined Cx 32 mRNA and protein expression in the pancreas. Methods: Cx 32 mRNA and protein expression in the pancreas was examined by Northern blot analysis and Western blot analysis, respectively, 1, 4, 7, and 14 days after the induction of acute pancreatitis. Results: Cx 32 mRNA was identified in normal rat pancreas, and the value for the relative intensity against 18S rRNA was 0.57 ± 0.15 (mean ± SD). After the induction of acute pancreatitis by caerulein, the Cx 32 mRNA expression levels were increased on day 1, day 4, day 7, and day 14 compared with levels in the normal pancreas (1.63-fold, 1.61-fold, 1.49-fold, and 1.35-fold, respectively). A significant increase in Cx 32 protein expression was detected on day 1 and day 4 (1.67 ± 0.15-fold and 1.72 ± 0.2-fold, respectively), while Cx 32-positive spots, determined by immunohistochemical analysis, were markedly decreased on day 1 and had returned to normal by day 14. Conclusions: These results show that the expression of Cx 32 increases early on after the induction of pancreatitis by Cn, and that the normalization of Cx 32-immunostained spots in Cn-induced acute pancreatitis occurs after the increase in Cx 32 mRNA and protein expression.