Establishment of a pancreatic β cell proliferation model in vitro and a platform for diabetes drug screening

Diabetes, a disease resulting from loss of functional beta cells, is globally an increasingly important condition. Based on the islet-differentiation ability of ductal epithelial cells and stimulating beta cell proliferation ability of the Reg I alpha gene, we aimed to establish an in vitro pancreatic beta cell proliferation model for screening therapeutic drugs of diabetes in the future. Pancreatic ductal epithelial cells were isolated from male Wistar rats, and induced to differentiate into pancreatic beta cells. Immunofluorescence staining assay, western blot, RT-PCR analysis, and dithizone staining were used to characterize the cells. Rat Reg I alpha protein was transiently expressed in vitro by transfection of HEK 293 cells with the PCMV6-entry-REG Ia plasmid, and expression was verified by RT-PCR analysis, proliferation assay, and apoptosis assay. The pancreatic beta cell proliferation model was further validated by a proliferation assay using differentiated pancreatic beta cells treated with transfection supernatant. Finally, we have successfully established an in vitro pancreatic beta cells proliferation model using transiently expressed rat Reg I alpha protein and differentiated pancreatic beta cells from pancreatic ductal epithelial cells. This model could be used as a platform to screen new drugs for islet neogenesis to cure diabetes, especially Chinese herbal drugs in the future.