[Differentiation of bone marrow mesenchymal stem cells into insulin producing cells induced by rat injured pancreatic tissue extract]

Abstract

Objective: To investigate the effects and mechanisms of differentiation of bone marrow mesenchymal stem cells (BMSCs) into insulin producing cells (IPCs) induced by injured pancreatic tissue extract of rat.

Methods: Eighty 6-week-old Sprague Dawley rats were selected. Forty rats underwent removal of 60% pancreas and the injured pancreas tissue was obtained after 48 hours to prepare the injured pancreatic tissue extract; and normal pancreatic tissue extract was prepared from the other 40 rats. The BMSCs were isolated from the tibia and femur of 4-week-old Sprague Dawley rats. BMSCs at passage 3 were co-cultured with rat injured pancreatic tissue extract as experimental group, with rat normal pancreatic tissue extract as normal control group, and with cell culture medium as blank control group for 14 days. The expressions of pancreas development related genes and proteins were detected, and cell morphological changes were observed. Then the C peptide positive cell rate was detected by flow cytometry analysis and insulin secretion levels were detected by glucose stimulation experiment at 14 days.

Results: Injured pancreatic tissue extract can induced BMSCs differentiating into IPCs. The pancreatic development related genes of pancreatic duodenal homeobox 1 (PDX-1), islet 1, Nkx6.1, glucose transporter type 2, proprotein convertase 2, neurogenin 3, and somatostatin were expressed sequentially in the differentiation process of experimental group; mature pancreatic proteins of PDX-1, insulin, C peptide, Nkx6.1 also were expressed. But there was no morphological changes and expression of pancreatic development related genes and proteins in normal control and blank control groups. The C peptide positive cell rate of experimental group (13.8% +/- 1.8%) were significantly higher than those of normal control and blank control groups (1.6% +/- 0.4%) (P < 0.05). The insulin secretion of experimental group was significantly higher than that of normal control and blank control groups (P < 0.05), but it was 1/40 and 1147 of natural islet cells (P < 0.05).

Conclusion: After pancreatic injury, injured pancreas would secrete transcription proteins related to development, differentiation, and repair of pancreas, which can promote the differentiation of BMSCs into IPCs.