| Objective:Mesenchymal stem cells transplantation(MSCT) has been recentaly become a novel therapy for patients with new-oneset type 1 diabetes(T1D).To investigate the efficiency and the underlying mechanism by bone marrow mesenchymal stem cells transplantation for T1D.Methods:Established type 1 diabetes models in NOD mice by injecting with 40-50mg/kg streptozotocin(STZ) intraperitoneally for consecutive five days, three days later, blood glucose was measured,these mice whose non-fasting blood glucose≥13.9mmol/1 for 2 consecutive days were diagnosed as diabetic mice. and then were randomly divided into three groups:1,Diabetes Control(DC) group(n=32 mice:0W=6 2W=6 4W=10 8W=10);Low-dose Bone Marrow Mesenchymal stem cells Transplantation(LBMT) group(n=18 mice:2W=6 4W=6 6W=6 BMSC2*106 in lml saline); High-dose Bone Marrow Mesenchymal stem cells(HBMT) group(n=18mice:2W=6 4W=6 6W=6 BMSC6*106 in lml saline), four time periods(0W:the time to be the models,2W: the two week after transplantation or the two week after being models,4W:the four week after transplantation or the four week after being models,6W:the six week afte transplangtation or the six after being models). Mice were transplanted with BMSCs via tail vein. Blood glucose were monitored every week. All the mice were killed and their spleen lymphocytes were collected in different stages. Collecting the blood from orbital venous. The proportion of Treg cells,Th cells,Tc cells cells were analyzed by flow cytometry. The serum levels of cytokines IFN-γ,IL-10,TGF-βwere determined by ELISA.The pancreases were dyed by HE to be observed the pancreatic structure,and IHC method was used to detect the content of insulin in the islets.Results:Three days after the first STZ-injection, the blood glucose level gradually increased. The blood glucose of the transplantation groups were lower than that in DC group after transplantation, especially in HBMT group. The differenc was significant between transplantation groups and control group until the five weeks after transplantation. The blood glucose of the transplantation groups were still lower six week after transplantation.Compared with the control group, the ratio of Tc cells in spleen all droped in transplantation groups in different stages, the ratio in HBMT group droped significantly in the four week. The ratio of Th cells did not change significantly in the three groups in different stages. In the transplantation group,the ratio of Treg cells was higher than that in DC group after transplantation. In the HBMT group,the ratio rised significantly(P<0.05 to DC group) in different stages, and in the two weeks(to LBMT group). In the LBMT group, the ratio rised not obviouslyCompared with the control group, the levels of IFN-Y was lower, the level of IL-10, TGF-βwere higher in the both experimental group. The level of IFN-Y, TGF-βshowed significant difference between the HBMT group and DC group.After mading models success,the pancreas structure was much damaged. As diabetic medical history extend,islet structure was damaged more seriously.Islet number reduced obviously. But after transplantation, Islet number was more than that in DC group.The islet structure was relatively complete.and a few new ialet structure was found.These transformations were obvious in HBMT group.Conclusions:1,Transplantation BMSCs can reduce type 1 diabetes 1,hyperglycemia condition. The transplant' dosage and the curative effect have certain relevance.2,The percentage of Tregs in the spleen was correlated with the attenuation of hyperglycemia. After BMSCs transplantation, the ratio of Tc cells and the level of IFN-γdecreased, the level of IL-10/TGF-βincreased, which may be the immune mechanism of BMSCT therapy in T1D.3,MSC can improve the islet structure,and can facilitate isletβcells proliferation directly or indirectly. and so can inceases insulin secretion. |
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