Abstract: Objective By comparing rat pancreatic extract(RPE) with nicotinamide, we explored a more effective method for inducing mouse bone marrow mesenchymal stem cells(BMSCs) into insulin producing cells. Methods RPE and nicotinamide were used to trans-differentiate mouse BMSCs into insulin producing cells. After trans-differentiation, the two methods induced insulin producing cells(IPCs) were detected by immunocytochemistry to compare the insulin expression in cytoplasm and detected trans-differentiation extent by diphenylthiocarbazone(DTZ) staining. Insulin releasing curve of IPCs exposed to 25mmol/L glucose and C peptide expression were detected by Radioimmunoassay(RIA). Four pancreatic islets associated mRNA (Ins-1,Ins-2,Glut-2 and GK) expression by RT-PCR technology. Then we analyzed and compared trans-differentiation effect between the two methods. Result From immunocytochemistry of insulin, we found that insulin producing cells trans-differentiated by both methods and all could secrete insulin and no significant staining extent difference was observed. And also there was no difference between them in DTZ stain and morphology pictures. However RIA showed the evident difference between them. The insulin releasing curve by the IPCs exposed to 25mmol/L glucose showed that nicotinamide induced IPCs were not like RPE induced cells which were more similar to mouse pancreatic islets. Moreover, the nicotinamide induced BMSCs could not express C peptide, and the RPE induced BMSCs expressed C peptide. RT-PCR showed nicotinamide and RPE induced BMSCs could all express the islets related mRNA (Ins-1, Ins-2, Glut-2, GK). Conclusion As compared with Nicotinamide, RPE seems to be a more effective inducer to trans-differentiate BMSCs into IPCs.

Key words: Bone marrow mesenchymal stem cell, Rat pancreatic extract, Insulin producing cell, Nicotinamide, Rodioimmunoassay, Rat, Mouse