BACKGROUND: Mesenchymal stem cells have self-replicating, immune tolerance and tissue repair characteristics. Type 1 diabetes mellitus is an autoimmune disease mainly resulting from islet beta-cell damage. In view of this, mesenchymal stem cells can be considered to prevent and treat type 1 diabetes mellitus.
OBJECTIVE: To observe the effect of umbilical cord mesenchymal stem cell transplantation on the newly-onset type 1 diabetic mice (NOD mice).
METHODS: Type 1 diabetes model mice (NOD mice) were selected and divided into control group (Group A, mice without onset were injected with normal saline 1 mL into the tail vein), interventional group (Group B, onset mice were injected with 1 mL stem cells into the tail vein, 1 × 106 cells per mouse), and group without injection of umbilical cord mesenchymal stem cells after onset (Group C, onset mice were injected with normal saline 1 mL into the tail vein). Three months later, blood glucose and daily insulin dose were detected; the number and proportion of CD4+, CD8+T cells and CD4+CD25+ regulatory T cells were determined using a flow cytometry; levels of interleukin-2, interleukin-10 and tumor necrosis factor alpha were detected using enzyme linked immunosorbent assay; and fasting and 2-hour postprandial C-peptide levels were detected using enzyme-linked immunosorbent double antibody sandwich method. Islet morphology and lymphocyte infiltration were observed based on pathological sections. The number and size of the islet α and β cells were determined by using immunohistochemical method.
RESULTS AND CONCLUSION: (1) Compared with the group C, the immunohistochemical results confirmed that infiltration of lymphocytes in the group B was significantly reduced, the structure of islet α and β cells was more complete and the number of α and β cells was significantly increased and consistent. (2) Compared with the group C, the CD4+ T cell number and the rate of CD4+/CD8+ T cells in the group B were lower (P < 0.05), while the number of CD4+ CD25+ regulatory T cells in the group B was higher (P < 0.01). (3) Compared with the group C, the tumor necrosis factor-α level was significantly lower in the group B, but interleukin-10 level was increased in the group B (P < 0.01). (4) Compared with the group C, the group B had lower blood glucose level and insulin dose, but a higher C-peptide level (P < 0.05). It is indicated that umbilical cord-derived mesenchymal stem cells have a positive effect on the treatment of onset type 1 diabetes mellitus, which can reduce blood glucose level and insulin dose.