The role of nitric oxide in caerulein-induced acute pancreatitis and the recovery process after inflammatory damage

Objectives Nitric oxide (NO) is involved in the control of pancreatic blood flow and secretion, and its role in the maintenance of pancreatic tissue h as been suggested. The aim of our study was to evaluate the influence of NO on pancreatic trophic parameters during acute pancreatitis induction and t he pancreas recovery process. Design/methods Acute pancreatitis was induced in rats by a supramaximal dos e of caerulein. During acute pancreatitis induction, rats were treated with L-arginine (a substrate for NO synthesis), glyceryl trinitrate (NTG, NO do nor), glycine, NG-nitro-L-arginine (L-NNA, NO synthase inhibitor), L-argini ne + L-NNA, or saline. Pancreatic weight, total contents of RNA, DNA, prote in, amylase and chymotrypsin as well as pancreas histology and the number o f proliferating acinar cells were evaluated after pancreatitis induction in all groups and additionally after 7 and 14 days of recovery in untreated a cute pancreatitis rats or those injected with L-NNA and/or L-arginine. Results Pancreas destruction after acute pancreatitis was evidenced by simi lar decreases of all parameters in untreated acute pancreatitis rats or tho se treated with L-NNA or glycine when compared to control healthy animals. The recovery process after acute pancreatitis was not affected by L-NNA inj ections; however, the increased cell proliferation occurred later than in u ntreated rats. NTG and especially L-arginine treatment resulted in signific ant attenuation of pancreas damage (partially prevented by L-NNA treatment) as evidenced by biochemical data with a slight improvement in morphology. Treatment with L-arginine alone or in combination with L-NNA resulted in au gmented cell proliferation after acute pancreatitis induction followed by e arlier recovery in comparison to untreated acute pancreatitis rats or the L -NNA-injected group. Conclusion The present study suggests the involvement of NO in mild acute p ancreatitis and in the recovery process after inflammatory damage. Eur J Ga stroenterol Hepatol 11:1019-1026 (C) 1999 Lippincott Williams & Wilkins.