Expression of stem cell markers CK-19 and PDX-1 mRNA in pancreatic islet samples of different purity from rats.

Background: Islet stem cells are more or less retained in the procedure of islet isolation and purification, and are transplanted together with islet grafts. Keratoprotein (CK-19) and pancreatic duodenal hox gene 1 (PDX-1) are markers of stem cells. This study was undertaken to examine the expression of these markers in pancreatic islet samples of different purity from rats.

Methods: A total of 30 male Sprague-Dawley rats were randomly assigned to 3 groups to undergo perfusion with V-type collagenase via the pancreatic duct, then the pancreas was excised, diced, shaken, digested and centrifuged to obtain islet sediments. The sediment from group A was not purified, while that from group B was purified with 25% Ficoll-400 and that from group C with 25% and 11% Ficoll-400. RNA was extracted from the different islet samples for reverse transcriptase-polymerase chain reaction (RT-PCR). The expression of the pancreatic stem cell markers CK-19 and PDX-1 was assessed.

Results: The purity of islets in samples was (43.6+/-6.29)% in group A; (65.3+/-4.40)% in group B; and (77.6+/-6.36)% in group C (P<0.05). The expression of CK-19 and PDX-1 mRNA was significantly higher in group A than in groups B and C, but group C showed the lowest level of expression.

Conclusion: The expression of CK-19 and PDX-1 mRNA in islet samples of different purity suggests the presence of stem cells in all islet samples.