Morphological Changes in the Endocrine and Exocrine Pancreas of Rats after Experimental Obstructive Jaundice

Abstract

Obstructive jaundice causes multiple malfunctions in various organs, including the pancreas. It is not yet known, however, how this occurs. In the present study, we experimentally induced obstructive jaundice through bile duct ligation (BDL) in rats. We measured serum bilirubin, amylase and insulin levels and examined histological, immunohistochemical and cytological changes in the pancreas at 3 days, 1 week, and 4 weeks after the BDL. Morphometrical analysis was also conducted. Serum amylase levels steeply increased at 3 days and then decreased at 1 and 4 weeks after the BDL to lower than the control level. In contrast, the number of zymogen granules decreased at 3 days after the BDL, then increased and eventually surpassed the control group. On the other hand, serum insulin levels dramatically decreased at 3 days after the BDL, and then, at 1 week after the BDL, recovered to a level close to that of the control group. At 4 weeks after the BDL, however, the serum insulin levels again showed a marked decline. Slight decrease in insulin immunoreactivity and number of insulin granules were observed at 4 weeks after the BDL. Cholecystokinin receptors (CCK-R) were expressed in both acinar and islet cells; their immunoreactivity significantly decreased in the acinar cells at 4 weeks after the BDL. Our results suggest that CCK may play a role in regulating changes in the pancreas after obstructive jaundice.