In the present study, aMSCs were efficiently reprogrammed into islet β-cells (reprogrammed aMSCs-derived islet β-cells, ra-βCs) using a six-gene combination composed of Pbx1, Rfx3, Pdx1, Ngn3, Pax4 and MafA. The immunogenicity of ra-βCs was detected, and ra-βCs and aMSCs were cotransplanted to treat a canine type I diabetes mellitus model and in the clinic, which achieved ideal therapeutic effects, providing a theoretical basis and therapeutic method for the treatment of canine type I diabetes mellitus. The gene discussed is PAX4; the disease is type 1 diabetes mellitus.