Ischemic preconditioning reduces the severity of ischemia/reperfusion-induced pancreatitis

In various organs, including heart, kidneys, brain, liver and stomach, preconditioning by brief exposure to ischemia protects the organ against damage evoked by subsequent severe ischemia. This study has been undertaken to check whether two brief ischemic periods protect the pancreas against severe ischemia/reperfusion-induced pancreatitis and, if so, what is the role of sensory and vagal nerves in this phenomenon. In male Wistar rats, the ischemic preconditioning of the pancreas was performed by clamping of celiac artery (2 x 5 min with 5 min interval). Thirty minutes after preconditioning or sham operation, the ischemia/reperfusion-induced pancreatitis was evoked by clamping of inferior splenic artery for 30 min using microvascular clips, followed by 1 h reperfusion. Sensory nerves ablation was induced 10 days before final experiments by capsaicin. Truncal vagotomy was performed 1 week before the experiment. Exposure to regular 30-min pancreatic ischemia followed by 1 h reperfusion led to the development of acute hemorrhagic pancreatitis. Ischemic preconditioning, applied prior to induction of pancreatitis, caused the reduction in plasma lipase, plasma interleukin-1beta and histological signs of pancreatic damage, as well as attenuated the reduction in pancreatic blood flow and DNA synthesis. Ablation of sensory nerves by capsaicin caused an aggravation of ischemia/reperfusion-induced pancreatic damage and attenuated a protective effect of ischemic preconditioning. Noxious effect of sensory nerves ablation on the pancreas was accompanied by the reduction in pancreatic blood flow and an increase in plasma interleukin-1beta. Similar but less pronounced deleterious effect on the pancreas was observed after vagotomy. We conclude that: (1) pancreatic ischemic preconditioning reduces the severity of ischemia/reperfusion-induced pancreatitis; (2) this effect seems to be related, at least in part, to the improvement of pancreatic blood flow and the reduction in the release of proinflammatory interleukin-1beta; (3) sensory and vagal nerves are involved in protective effect of ischemic preconditioning against pancreatic damage.