Protective Effect Of Hypoxia Preconditioned Mesenchymal Stem Cells On Pancreatic Injury In Mice With Severe Acute Pancreatitis

Objective:To investigate the protective effect of hypoxic preconditioned placental mesenchymal stem cells(HP-MSCs)on severe acute pancreatitis(SAP)in mice,and to explore its possible mechanism.To provide a scientific basis for the clinical treatment of severe acute pancreatitis with stem cells.Methods:Placental mesenchymal stem cells(P-MSCs)were cultured under normal oxygen(21%oxygen concentration)and hypoxic(1%oxygen concentration)conditions,respectively.CCK-8 and MTT methods were used to detect the activity and migration ability of P-MSCs at different oxygen concentrations.Thirty-two healthy adult male C57BL/6 mice were randomly divided into sham operation group(Sham group),SAP group,normal oxygen group(P-MSCs group)and hypoxia group(HP-MSCs group)with 8 mice in each group.SAP model of mice was established by retrograde injection of 4%sodium taurocholate into pancreatic bile duct.6 hours after modeling,P-MSCs group was injected with P-MSCs(1×10~6/100g,2×10~6/m L)through tail vein,and HP-MSCs group was injected with HP-MSCs(1×10~6/100g,2×10~6/m L)through tail vein.All mice were sacrificed 12 hours after modeling.Serum and pancreatic tissue were collected.HE staining was used to evaluate the degree of pancreatic tissue injury and pathological score was performed.Serum amylase,lipase and inflammatory factors were measured by enzyme-linked immunosorbent assay(ELISA).The expressions of RIP3,MLKL,p-MLKL and NLRP3 in mouse pancreas were detected by Western blot.Results:HP-MSCs showed better activity and proliferation ability than P-MSCs in vitro.In mice,compared with SAP group,pancreatic pathological scores in P-MSCs group and HP-MSCs group were decreased(P<0.05).Serum concentrations of amylase,lipase,IL-6,and TNF-αwere decreased(P<0.05),but the changes were most obvious in HP-MSCs group.Western blot showed that the expressions of RIP3,P-MLKL and NLRP3 in pancreatic tissues of HP-MSCs were significantly lower than those in SAP and P-MSCs groups(P<0.05).Conclusion:Compared with P-MSCs,HP-MSCs can significantly reduce SAP,and the mechanism may be related to the inhibition of RIP1/RIP3-MLKL signaling pathway.