Exploring The Therapeutic Effects Of Rutaecarpine Against Acute Pancreatitis Via Calcitonin Gene-related Peptide And Its Underlying Mechanisms

Background and purpose:Acute pancreatitis（AP）is an inflammatory disease caused by early activation of pancreatic enzymes caused by various etiologies,which causes pancreatic tissue self-digestion,edema,hemorrhage and even necrosis in the pancreas.AP is a life-threatening disease that affects several million people worldwide with increasing morbidity rates.However,currently available treatment regimens for AP exhibit limited efficacy owing to the lack of specific therapeutic targets.Therefore,research on new strategies for the treatment of AP and potential drug therapeutic targets has become the focus of research on AP.The pathogenesis of AP is complex.Pancreatic inflammation and pancreatic tissue necrosis are considered to be the most important initial pathological factors in the process of AP.Rutaecarpine is the main active ingredient of Chinese herbal drug Wu-Chu-Yu,which has a wide range of biological and pharmacological effects.Previous studies have reported that rutaecarpine can exhibit significant anti-inflammatory and immunomodulatory effects through multiple targets,and the molecular target of most pharmacological effects of rutaecarpine has been confirmed to be CGRP release and mediation.Therefore,in this study,we explored the therapeutic effects of rutaecarpine on AP from the mice and AR42J cells,and we also explored the dependence on CGRP.This study aimed to provide new insight and therapeutic targets for anti-inflammatory treatment of AP.Methods:We used the AP model of mice induced by cerulein combined with LPS,and we constructed CGRP gene knockout(CGRP^-/-)mice for the animal experiments.After the induction of AP model and treatment of rutaecarpine in the wild-type mice and CGRP^-/-mice,we observed the pathological changes of the pancreatic tissue,the changes of pro-inflammatory and anti-inflammatory cytokine levels,and the critical protein phosphorylation levels of MAPK,NF-κB,as well as the STAT3signal transduction pathways in mice,and then we investigated the effects of rutaecarpine on cerulein/LPS-induced AP in vivo and its underlying mechanisms.Similarly,the induction of AP model was also performed in the AR42J cells,and CGRP overexpression plasmids or CGRP-sh RNA plasmids were transfected into AR42J cells.After the AR42J cells treated with rutaecarpine,we observed the changes of pro-inflammatory and anti-inflammatory cytokine levels,the apoptosis rate of pancreatic cells,and the changes of critical protein phosphorylation level of MAPK,NF-κB and STAT3 signal transduction pathways,and then we investigated the effects of rutaecarpine on cerulein-induced AP in vitro and its underlying mechanisms.Results:1.In cerulein/LPS-treated wild-type mice,but not CGRP gene knock-out mice,rutaecarpine significantly ameliorated pancreatic inflammation by alleviating histopathological changes,reducing IL-6,IL-12 and TNF-αlevels,and increasing in IL-10 levels.Moreover,rutaecarpine improved AP by suppressing the MAPK and NF-κB signaling pathways.These effects were mostly mediated through CGRP.2.Cell-based studies revealed that rutaecarpine significantly improved cell viability while suppressing the apoptosis of AR42J cells with cerulein-induced AP,downregulating IL-6 and TNF-α,stimulating IL-10 release,and inhibiting MAPK,NF-κB,and STAT3 signaling activation,all in a CGRP-dependent manner.Conclusion:Rutaecarpine ameliorated cerulein/LPS-induced AP inflammatory responses in mice and AR42J cells in a CGRP-dependent manner and thus may represent a potential therapeutic option for AP patients.Our study provides valuable insights for AP drug development.