Protective Effect Of Heat Shock Factor 1 On Mice With Caerulein-Induced Acute Pancreatitis And The Expression Of SDF-1/CXCR4

Background Objective:Heat shock factor 1(HSF1)has protective effect on mice with caerulein-induced acute pancreatitis,but its protective mechanism is still unclear;chemokine stromal cell-derived factor-1(SDF-1)and CXC chemokine receptor 4(CXCR4)can affect the occurrence and development of inflammation,but there is no research on their expression in pancreatitis;HSF1 has regulatory effect on inflammatory genes,but there is no research on the regulation of HSF1 on chemokine SDF-1/CXCR4.The aim of this study was to construct the stable ShRNA-HSF1-transfected rat exocrine pancreatic cells(AR42J)and establish the pancreatitis model.The acute pancreatitis(AP)model was established in HSF1 knockout(HSF1-/-)and wild(HSF1+/+)mice by using caerulein,and to explore the protective effect of HSF1 on caerulein-induced AP in mice and AR42J cells and the effect of HSF1 on SDF1/CXCR4 expression.Methods:1.AR42J cells were used to establish stably transfected shRNA-HSF1 AR42J cells,and the HSF1+/+ and HSF1-/mice with pancreatitis model was constructed by Caerulein treatment;the HSE sequence of SDF-1 gene promoter was cloned and electrophoretic mobility shift analysis(EMSA)was performed to observe whether HSF1 can bind to HSE in the promoter region of the gene;the transcriptional activity of SDF-1/CXCR4 was detected by luciferase reporter gene;the expression of SDF-1/CXCR4 mRNA was analyzed by RT-PCR;the protein of SDF-1 was analyzed by ELISA.Apoptosis was detected by annexin V-FITC.2.Adult male HSF1-/-mice and HSF1+/+ mice(about 16W,25g)were randomly assigned into 4 groups:HSF1+/++NS group,HSF1+/++caerulein group,HSF1-/-NS group and HSF1-/-+caerulein group.The acute pancreatitis model was established by intraperitoneal injection of rulein at a dose of 50μg/kg for 7 hours at an interval of 1 hour.The control mice were injected with normal saline for 7 times,and the mice were killed 24 hours after treatment with caerulein.The pancreatic tissues of the mice were taken for HE staining and pathological score,and the serum was collected to detect the amylase activity by starch iodine colorimetry.The mRNA expression level of SDF-1/CXCR4 was analyzed by RT-PCR.The protein expression of SDF-1 was analyzed by ELISA.The expression of SDF-1/CXCR4 protein was detected by immunohistochemistry.Results:in AR42J cells,EMSA showed that HSF1 could bind to the HSE sequence in the promoter region of SDF-1 gene.Luciferase reporter gene,RT-PCR,ELISA and apoptosis detection showed that the transcriptional activity and mRNA expression of SDF-1/CXCR4,protein expression of SDF-1 and apoptosis expression of AR42J cells transfected with HSF1-/-and HSF1+/+ were low and no significant difference was found.In the mouse model,HE staining and pathology score,pancreatic histopathology score and serum amylase were up-regulated after treatment with caerulein.Compared with HSF1+/+ mice,the HE staining and pathology score,pancreatic histopathology score and serum amylase in HSF1-/-mice were up-regulated more significantly.RT-PCR showed that the mRNA expression levels of SDF-1 and CXCR4 were up-regulated after treatment with Caerulein.SDF-1 mRNA and CXCR4 mRNA were up-regulated more obviously in HSF1-/-mice compared with HSF1+/+mice.ELISA and immunohistochemistry indicated that SDF-1/CXCR4 protein expression was more up-regulated in cerulein induced-HSF1-/-compared with cerulein induced-HSF1+/+ mice.Conclusion:1.HSF1 can inhibit apoptosis and pancreatic pathological injury of AR42J cells and mice with pancreatitis induced by cerulein;2.The expression of SDF-1/CXCR4 is increased in AR42J cells and mice with pancreatitis induced by cerulein;3.HSF1 can regulate SDF-1/CXCR4 at transcriptional level and inhibit the expression of SDF-1/CXCR4 mRNA and protein.