The Experimental Research On The Expression And Significance Of NOTCH Signal In Acute Pancreatitis

Part I Different expression of NOTCH signal on mild andsevere acute pancretitis[Objiective] To investigate the role of NOTCH signal pathway in mild and severe acute pancreatitis by detecting the expression of NOTCH-1, CBF-1 and HES-1.[Method] Mild and severe acute pancreatitis model wrer established by retrograde injection of different dose sodium taurocholae into pancreatic duct. The NOTCH pathway molecules were examined by western blot and real-time PCR in different type acute pancreatitits at different time. [Results] ①Both the protein and mRNA of NOTCH pathway molecules were elevated in the two groups; ②The NOTCH-1 and HES-1 rose higher in sever acute pancreatitis than that in mild acute pancreatitis. ③The peak time of NOTCH pathway molecules expression was at the 12th hour after the onset of mild acute pancreatitis, while it was at the 8th hour after the onset of severe acute pancreatitis; ④HES-1 increased higher than NOTHC-1 in both groups.[Conclusion] ①There exits amplification in NOTCH signal pathway;②The severity of acute pancreatitis was concerned with the time and degree of elevation in NOTCH pathway molecules; ③The elevation of NOTCH pathway molecules may be related to tissue regeneration and repair in acutepancreatitis.Part II The experimental research on NOTCH signal pathway andapoptosis in acute pancreatitis[Objective] To investigate the possible relationship between NOTCH molecules and apoptosis in acute pancreatitis.[Methods] The apoptosis were examined by TUNEL and the expression of NOTCH-1 and HES-1 were detected by western blot and real-time PCR in different type of acute pancreatitis at different time intervals. [Results] ①The apoptosis index did not change significance since 4 hours after the onset of mild acute pancreatitis; ②The peak of apoptosis index is at the 4th hour after the onset of sever acute pancreatitis. Then it decreased and the cell necrosis increased with time. ③The apoptosis index was much higher in mild acute pancreatitis than that in severe acute pancreatitis (P<0. 01) ; ④The protein and mRNA of NOTCH-1 and HES-1 were significant higher in severe acute pancreatitis than that in mild acute pancreatitis; ⑤The peak time of NOTCH pathway molecules expression was later than that of apoptosis index.[Conclusions] ①Both apoptosis and NOTCH pathway molecules expression were distinct in different type of acute pancreatitis; ②In mild acute pancreatits, the elevation of NOTCH pathway molecules may be related to tissue regeneration and repair while independed with apoptosis. ③In sever acute pancretitis, the elevation of NOTCH pathway molecules may inhibit apoptosis and promote necrois.Part III The anti-apoptotic effect of NOTCH signal activation on acinar cell[Objiective] To obtain expressing vector pcDNA3. 0 and to investigate the anti-apoptotic effect on acinar cell of the NOTCH-1 actived fragment(NICD).[Method] Expressing vector encoding NICD(pcDNA3. (HVICD) was constructed. After the pcDNA3. 0-NICD was transfected into acinar cell line AR4-2J, we used cerulein to induce apoptosis in the cell, and compared the apoptosis index with control.[Results] DNA sequencing and Endonuclease analysis showed that the NICD cDNA was cloned into pcDNA3.0 and the apoptosis index declined significantly by transfecting pcDNA3. 0～NICD into acinar cells. [Conclusion] ①Expressing vector pcDNA3.0-NICD was constructed successfully. ②NICD can inhibit acinar cell apoptosis.