The Role And Mechanism Of Macrophage Migration Inhibitory Factor In Acute Pancreatitis

Background and PurposeAcute pancreatitis(AP)is a life-threatening inflammatory disease with the characteristics of acute onset,serious illness,many complications,and high mortality.In all AP cases,about 20%-30%are complicated by systemic inflammation,which leads to multiple organ dysfunction and a mortality rate of up to 15%.It is generally believed that the occurrence and severity of AP depends on the response of pancreatic acinar cells to trypsinogen activation,and subsequent acinar cell damage and self-digestion.At present,domestic and foreign studies on the pathogenesis of AP mainly focus on inflammatory pathways,inflammatory factors,oxidative stress and calcium overload,etc.,the specific molecular mechanism of AP is still unclear.At this stage,the general treatment principles for AP are fasting and water deprivation,gastrointestinal decompression and medical treatment(including antispasmodic,analgesic,protease inhibitor and pancreatin inhibitor treatment,etc.).The treatment can be performed according to the needs of the disease,fluid resuscitation,intensive care treatment,treatment of complications,nutritional support,antibiotic application and surgery.Therefore,there is an urgent need to improve the understanding of the progression of AP disease,and studying the pathogenesis of AP has more important socioeconomic significance.Macrophage migration inhibitory factor(MIF)as an important pro-inflammatory factor,is a member of the bioactive protein family and can be released by a variety of cells.Monocytes/macrophages are the main source of MIF.MIF has a variety of biological functions and is involved in the pathogenesis of diseases such as sepsis,rheumatoid arthritis,glomerulonephritis,colitis,and chronic obstructive pulmonary disease.Previous studies have found that patients with severe acute pancreatitis(SAP)have significantly higher serum MIF levels than patients with mild acute pancreatitis(MAP)and healthy controls.There is a correlation between MIF and AP,but the specific role of MIF in the pathogenesis of AP is unclear.This study aims to verify the correlation between MIF and the occurrence and development of AP based on clinical issues,and to use Mif gene knockout(KO)mice as research objects to explore the role of MIF in the pathogenesis of AP.And its effect on wild type(WT)mice were pretreated with MIF inhibitor ISO-1 before induction of AP to investigate the role of MIF in L-arginine-induced AP animal models.Methods1.Collect blood samples from clinical AP patients(H-AP group)and healthy controls(H-Con group),record the blood amylase and lipase expression levels of each subject,and perform statistical analysis.The serum MIF expression level of each subject was detected by ELISA method and statistical analysis was performed.2.The serum expression levels of amylase,lipase,MIF and inflammatory factors(TNF-? and IL-1?)in each group of experimental mice were detected by ELISA and statistical analysis was performed.3.The histological H&E staining was used to detect the pathological damage of pancreatic tissue in each group of experimental mice and the pathological scores were statistically analyzed.4.Detect the expression levels of MIF,NF-?B,TNF-? and IL-1? mRNA in the pancreatic tissue of each experimental mouse by RT-PCR and perform statistical analysis.5.Analysis of the expression of MIF,NF-?B,TNF-? and IL-1? in the pancreatic tissue of each group of experimental mice by immunohistochemical staining and conduct semi-quantitative comparative analysis.Results1.Compared with the H-Con group,the serum amylase and lipase levels in the H-AP group were significantly increased,and the difference was statistically significant;the serum MIF levels in the H-AP group were significantly increased,compared with the serum amylase and lipase levels.The differences in expression levels have a consistent trend,and the differences are statistically significant.2.Compared with the WT group,the expression levels of serum amylase,lipase,TNF-? and IL-1? in the KO group were significantly reduced;compared with the AP group,the serum MIF,the expression levels of amylase,lipase,TNF-? and IL-1?were significantly reduced.3.Compared with the WT group,the pancreatic tissue of the KO group was significantly less damaged,and the edema,inflammation,necrosis and total pathological scores were significantly reduced;compared with the AP group,the degree of pancreatic tissue damage in the AP+ISO-1 group was ameliorated.Edema,inflammation,necrosis and total pathological scores were significantly reduced.4.RT-PCR analysis results showed that the expression levels of MIF,NF-?B,TNF-? and IL-1? mRNA in pancreatic tissue of KO group were significantly lower than those in WT group;the expression levels of MIF,NF-?B,TNF-? and IL-1?mRNA in pancreatic tissue of AP+ISO-1 group were significantly lower than those in AP group.5.Immunohistochemical analysis showed that compared with the WT group,the expression of TNF-?,IL-1? and NF-?B p65 in the pancreatic tissue of the KO group was significantly reduced;compared with the AP group,the expression levels of MIF,TNF-?,IL-1? and NF-?B p65 in pancreas tissue of the AP+ISO-1 group were significantly lower than those in the AP group.Conclusion1.Serum MIF levels are elevated in AP patients,and MIF involved in the development of AP.2.Mif gene knockout or MIF inhibitor ISO-1 can reduce the expression levels of inflammatory factors in serum and pancreatic tissues during AP,and reduce the activation of NF-?B pathway in pancreatic tissue,thereby reducing the pathological injury of pancreatic tissue and improving the inflammatory response of AP.3.Clinically,with MIF as the target,the pharmacological targeting of MIF with orally active MIF inhibitor or other biologically active antagonists for targeted inhibition of MIF may be a new way to prevent,treat and/or control AP.