PDX-1 expression and proliferation of duct epithelial cells after partial pancreatectomy in rats.
BACKGROUND
The pancreas has a strong regeneration potential in mammals. Previous studies suggested that pancreas regeneration is correlated with proliferation and differentiation of pancreatic stem cells, but the field of pancreatic stem cells is still in its infancy. This study was undertaken to detect the expression of pancreas/duodenal homeobox-1 (PDX-1) and proliferation of pancreatic duct epithelial cells in remnant pancreas during regeneration after partial pancreatectomy in rats, and characterize the source of pancreatic stem cells.


METHODS
Partial pancreatectomy (90%) was performed on four- to five-week-old Sprague-Dawley rats, and duct epithelial cells and acinar cells were detected by immunohistochemical staining and scored using the 5-bromo-2-deoxyuridine (BrdU) labelling index at various time points. Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to assess the expression of PDX-1 protein and mRNA, respectively.


RESULTS
At 24 hours after partial pancreatectomy, proliferation started in the main, large and small duct cells, and persisted in small duct cells to day 5. The experimental and control groups were significantly different (P<0.001). BrdU-positive acinar cells were greatly increased and reached a peak on day 5. PDX-1 protein was only faintly detectable in pancreatic ductal cells on day 1 after partial pancreatectomy. On days 2 and 3, a 2-3 fold increase in PDX-1 protein was observed, corresponding to the characteristic 42 kD protein in Western blotting. The operated and sham-operated groups also differed significantly (P<0.05). PDX-1 protein expression on days 5 and 7 after operation did not differ from that of the control group. RT-PCR revealed that PDX-1 mRNA expression did not significantly differ between the operated group and the sham-operated group at various time points.


CONCLUSIONS
Pancreatic stem cells in pancreatic ductal epithelial cells are involved in the regeneration of remnant pancreas and the expression of PDX-1 in ductal cells is due to posttranscriptional regulation.
Liu
Tao
T
Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Wang
Chun-You
CY
Gou
Shan-Miao
SM
Wu
He-Shui
HS
Xiong
Jiong-Xin
JX
Zhou
Jing
J
D000818:Animals; D001973:Bromodeoxyuridine / Q000494:pharmacology; D049109:Cell Proliferation; D004847:Epithelial Cells / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000096:biosynthesis*; D007150:Immunohistochemistry; D016381:Islets of Langerhans Transplantation / Q000379:methods; D010179:Pancreas / Q000473:pathology* / Q000601:surgery*; D010180:Pancreatectomy; D010183:Pancreatic Ducts / Q000378:metabolism / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology*; D015534:Trans-Activators / Q000096:biosynthesis*
D018398:Homeodomain Proteins; D015534:Trans-Activators; C084010:pancreatic and duodenal homeobox 1 protein; D001973:Bromodeoxyuridine