Induction of chemokines in rat pancreatic acinar cell injury

Introduction: The pathogenesis of chronic pancreatitis (CP), especially of acinar cell injury, is still unclear. Interleukin (IL)-8 is a chemokine that is involved in various inflammatory diseases. Aim: To examine whether IL-8 and other chemokines are expressed in experimental acinar cell injury. Methodology: IL-8 expression was analyzed in spontaneous CP in the WBN/Kob rat and in rat pancreatic acinar AR4-2J cells treated with various stimuli using reverse transcription-polymerase chain reaction (semi quantitative) and immunohistochemistry. Results: Chronic pancreatitis developed at 12 weeks in the WBN/Kob rats. IL-8, macrophage chemoattractant protein-1, and macrophage inflammatory protein-2 mRNA was expressed from 4 weeks and peaked at 12 weeks. Immunohistochemistry showed a strong expression of IL-8 in acinar cells, proliferating ductular cells, and interstitial infiltrating cells. In contrast, normal pancreatic tissues lacked IL-8 expression. Further, IL-8 mRNA and protein were detectable in AR4-2J cells treated with the various stimuli, such as menadione, tumor necrosis factor-a and transforming growth factor beta(1). Conclusion: These results suggest that IL-8 is expressed in the pancreatic parenchyma and infiltrates in CP and that it plays a role in the initial pathogenesis of CP together with other chemokines and cytokines.