ABSTRACT
Objective To study the therapeutic effect and immunologic regulation of human amniotic mesenchymal stem cells (hAMSCs) in rats with experimental type 1 diabetes mellitus (T1DM).Methods The hAMSCs from human amnion were isolated and cultured in vitro,then phenotype was analyzed by flow cytometry.T1DM were produced by administering streptozocin to rats.The rats were divided into normal control group (n =6),T1 DM model group (n =6),medium treated group (n =6),hAMSCs transplanted group(n =6),and insulin treated group(n =6).5 × 106of hAMSCs or vehicle were administered to rats via sublingual vein.Blood glucose levels of rats were recorded weekly in the groups for six weeks by Blood Sugar Meter.At the end of 6 weeks after hAMSCs transplantation,concentrations of plasma insulin were detected by ELISA; histopathological changes of pancreas,surviwl and differentiation of transplanted hAMSCs in pancreatic tissue were studied with HE staining,and immunofluorescence staining; percentages of lymphocyte subsets in peripheral blood mononuclear cells were determined by flow cytometry ; concentrations of plasma cytokines were determined by cytometric bead array.Results After hAMSCs transplantation,blood glucose levels in rats with T1DM were decreased (P ＜ 0.01),while concentrations of plasma insulin were increased significantly (P＜0.01).At 6 weeks,cell-treated animals showed an improvement in pancreas damage ; the percentages of CD4 + IFN-γ+ (Th 1) and C D4 + interleukin (IL)-17 + (Th 17) cells were reduced (all P＜0.05),while the percentages of FoxP3-positive regulatory T cells (FoxP3 +Treg) and CD4+ IL-4+(Th2) cells were increased (all P＜0.01) ; plasma concentrations of interferon-γ,IL-2,and tumor necrosis factor-αwere decreased (all P＜0.01),but IL-4 level was increased (P＜0.05).No histological evidence of insulin producing cells from hAMSCs was seen within pancreas.Conclusions hAMSCs may reduce blood glucose and alleviate the islet damage in rats with T1 DM,which is related to their potential to up-regulate FoxP3 +Treg cells.