[Immune changes in type 1 diabetes animal model after syngeneic bone marrow transplantation]

Syngeneic bone marrow transplantation (syn-BMT), as a novel therapy for type 1 diabetes (T1D), has been used more and more widely. This study was aimed to detect the changes of peripheral CD4(+) T lymphocytes, CD8(+) T lymphocytes, CD4(+)/CD8(+) T lymphocytes and NK cells before and after T1D mice were treated with syn-BMT, and to investigate the effects of these cells in T1D and the effects of syn-BMT-inducing immunotolerance. T1D mouse model was established by multiple low dose streptozotocin injection, the syn-BMT was performed on 10 day after the onset of diabetes. The T1D model mice were divided into group of diabetic mice treated with syn-BMT and group of diabetic control mice (DC), 6 normal C57BL/6J mice were regarded as normal control group (NC). On 30 day after syn-BMT, peripheral proportion of CD4(+) T lymphocytes, CD8(+) T lymphocytes, CD4(+)/CD8(+) T lymphocytes and NK cells were detected by flow cytometry. These cells of normal control mice (NC), diabetes control mice (DC) and diabetes mice treated by syn-BMT were also detected. Blood glucose level in three groups was assayed during the whole observation period. The results showed that syn-BMT could reduce blood glucose level of T1D mice to near normal (p > 0.05). Hematopoietic reconstitution happened in a month. The proportion of peripheral CD4(+) T lymphocytes, CD4(+)/CD8(+) T lymphocytes, NK cells all increased in new-onset diabetic mice (p < 0.01), while the proportion of peripheral CD8(+) T lymphocytes decreased (p < 0.01). On 30 day after T1D mice were treated with syn-BMT, the proportion of peripheral CD4(+) T lymphocytes was significantly lower than that in DC mice (p < 0.01), but still higher than NC (p < 0.05). The proportion of CD8(+) T lymphocytes was higher than that in DC and NC mice (p < 0.01). The ratio of CD4(+)/CD8(+) T lymphocytes and proportion of NK cells were both obviously lower than that in DC and NC mice (p < 0.01). It is concluded that the syn-BMT can reverse hyperglycemia and immune disorder in diabetic mice. On early period of diabetes onset, the proportions of CD4(+) T lymphocytes and NK cells, the ratio of CD4(+)/CD8(+) T lymphocytes increase, while proportion of CD8(+) T lymphocytes decreases in peripheral blood which mye be associated with onset of diabetes.