Effect of hypothermia on pancreatic acinar cells in rats.

This study was designed to evaluate the effects of direct pancreatic surface cooling on the exocrine pancreas. We measured the changes in serum amylase levels, pancreatic water, amylase and cathepsin B as a lysosomal enzyme, content, histological changes of acinar cells, and the subcellular distribution of cathepsin B after 1-2- and 3-hours of direct pancreatic cooling in rats. In addition, we evaluated the in-vivo amylase and cathepsin B output stimulated by caerulein, in-vitro lysosomal and mitochondrial fragility as well as the pancreatic adenylate energy metabolism. 2-hours cooling showed slight yet significant changes, but 3-hours cooling caused most significant changes including hyperamylasemia, increased pancreatic amylase content and very mild histological changes. Furthermore, 3-hours cooling caused a remarkable redistribution of cathepsin B activity from the lysosomal fraction to the heavier zymogen fraction, and colocalization of the lysosomal enzyme with the digestive enzyme, the impaired amylase and cathepsin B output into pancreatic juice stimulated by caerulein as well as the accelerated fragility of lysosomes and mitochondria, and impaired pancreatic adenylate energy metabolism. These results indicate the impaired exocrine pancreatic functions induced by direct pancreatic cooling injury induced by cooling as shown in the other models of experimental pancreatitis. Moreover, this cooling model of pancreatitis seems to be useful in understanding the early events in the pathogenesis of acute pancreatitis, and we must take these "cold" injuries of exocrine pancreas into considerations, particularly in the pancreas transplantation and in other major abdominal surgeries where the pancreas is exposed to cooling.