Study On The Expression Of Nestin And CD44 And The Proliferation And Differentiation Of Pancreatic Stem Cells During Pancreatic Injury Regeneration After Pancreatic Duct Ligation

Objective:To study the distribution,differentiation and proliferation of pancreatic stem cells in pancreatic tissue during regeneration after pancreatic injury,to explore the effect and mechanism of pancreatic mesenchymal stem cells and their secretory signals on pancreatic stem cell differentiation,and to provide relevant experimental basis for the molecular regulation mechanism of islet regeneration and the study of diabetes stem cell therapy.Methods:Pancreatic duct ligation(PDL)was used to construct a pancreatic injury regeneration model.35 healthy SD rats(both female and male,body weight 260±10g)were randomly divided into normal control group,sham operation group and model group,and the model group was further divided into PDL 1d group,PDL 3d group,PDL 5d group,PDL 7d group and PDL 9d group,a total of 7 groups of 5 rats were used.The model group constructed a PDL model by ligating the pancreatic body and tail and occluding the pancreatic body and the tail pancreatic duct.The sham operation group only opened the abdominal cavity to expose the pancreas and did not perform pancreatic duct ligation.The pancreatic head and pancreatic body and tail were taken from each group for histological treatment to observe the cell proliferation and differentiation in the pancreas tissue after pancreatic injury.The immunohistochemical SABC staining method,immunofluorescence double staining method and Western Blot technique were used to detect Nestin and CD44 Protein expression,distribution and changes.Results:(1)Normal control group and sham operation group:(1)In the normal control group and sham operation group,the number of Brd U positive cells is relatively small,mainly distributed in ductal epithelium,islet cells and acinar cells;(2)Nestin and CD44 in the normal control group and The sham operation group had a small amount of expression,and the positive cells were mainly distributed in the ductal epithelium and acinar cells.(2)PDL model group:(1)Distribution and counting of Brd U positive cells:The Brd U positive cells of the model group are mainly distributed in the ducts and acinus.Compared with the control group,the number of positive cells has no significant change at 1 d and the number of positive cells at 3 d increased significantly,and reached a peak on 5 d,and gradually decreased after 7 d.(2)Nestin expression:Compared with the control group,the expression of Nestin in the model group did not change significantly at 1 d,the expression increased significantly at 3 d,peaked at 5 d,and gradually decreased after 7 d.(3)CD44 expression:Compared with the control group,the expression of CD44 in the model group began to increase at 1 d,peaked at 5 d,and gradually decreased after 7 d.(3)Immunofluorescence double-staining results:The immunofluorescence double-staining results showed that pancreatic mesenchymal stem cells in the pancreas interstitium of the pancreas of the model group showed Nestin~+/Brd U~+,CD44~+/Brd U~+and CD44~+/Insulin~+immunopositive reactions.Conclusion:During pancreatic regeneration after pancreatic duct ligation,the expressions of Nestin and CD44 were obviously up-regulated,especially the mesenchymal stem cells in pancreatic interstitial cells proliferated massively,and were positive for Nestin,CD44 and Insulin.Pancreatic mesenchymal stem cells and their secreted factors may play an important regulatory role in the differentiation of pancreatic stem cells after PDL.The regulatory mechanism may be through the differentiation of mesenchymal stem cells and the activation and expression of their signals to form the microenvironment of pancreatic stem cell differentiation promotes the proliferation and differentiation of pancreatic stem cells.