Abstract: Object To investigate the cell distrubution and the therapeutic effect after BMSCs were injected into subcapsular pancreas of diabetic rats model. Methods BMSCs of male SD rat were labeled with enhanced green fluorescent protein (EGFP), administered them to diabetic rats by injecting into subcapsular pancreas at multiple points. Blood glucose levels, blood insulin levels and blood C-peptide levels were monitored, distribution of BMSCs were monitored by EGFP detection at 8 weeks after transplantation, EGFP and insulin double-positive cells were detected by immunofluorescence, EGFP and PDX1 double-positive cells were detected by fluorescence in situ hybridization (FISH) . Results Transplantation of BMSCs into pancreas reduced blood glucose,increased blood insulin and C-peptide in experimental diabetic rats, significantly differently from that of control group（P <0.05）. Up to 8 weeks after transplantation , cells of donor origin stabely expressed EGFP, and EGFP labled cells were distributed in islets (12.46%),blood vessel（4.4%）, acinus（9.24%）, and duct（3.21%）, the majority of EGFP labled cells were distributed in local focus （70.69%）. Immunofluorescence revealed double-positive cells of EGFP and insulin（5.16%）,FISH revealed double-positive cells of EGFP and PDX1（0.96%）.Conclusions Transplantation of BMSCs into pancreas effectively reversed hyperglycemia of experimental diabetes rat, transplanted BMSCs redistributed in pancreas, and transplanted BMSCs differentiated into insulin-secreting cells within pancreatic microenvironment.

Key words: pancreas, mensenchymal stem cells, experimental diabetic rats, transplantating, distrubution, insulin, differentiation