ABSTRACT
Objective@#To explore the levels of IL-22 in thymus damaged by γ-ray total body irradiation (TBI), and to study the role of IL-22 in T cell reconstitution after thymic injury induced by TBI.@*Methods@#To induce thymic injury, mice were treated by sub-lethal TBI. Levels of intra-thymic and circulatory IL-22 were detected by using ELISA assay. Untreated mice were used as control. After receiving sub-lethal TBI, mice were intraperitoneally injected with PBS or recombinant mouse IL-22, which were marked as TBI+PBS or TBI+IL-22, respectively. Mice were monitored for counts of total thymic cells and circulatory white blood cells. Flow cytometry was applied to analyze percentages of thymic epithelial cells (TEC), thymocyte subsets and circulatory T cells. Real-time PCR assay was applied to analyze the mRNA expression levels of Foxn1, Ccl25, Aire and Dll4 in thymus.@*Results@#①Sub-lethal TBI treated mice expressed higher levels of intra-thymic and circulatory IL-22, compared with untreated ones (all P<0.05). ②After injection of recombinant IL-22, TBI+IL-22 mice had higher levels of intra-thymic IL-22 than TBI+PBS mice (all P<0.05). ③On day 14 after irradiation, real-time PCR assay showed that TBI+IL-22 mice had higher mRNA levels of Foxn1, Ccl25, Aire and Dll4 in thymus compared with TBI+PBS ones. Meanwhile, the TBI+IL-22 mice had higher counts of total thymic cells[(5.93±3.19)×106/ml vs (1.42±0.46)×106/ml, t=3.128, P=0.033] and circulatory white blood cells[(3.08±0.94)×106/ml vs (1.43±0.30)×106/ml, t=3.730, P=0.015] than those of TBI+PBS mice. Flow cytometry analysis indicated that TBI+IL-22 mice had higher counts of TEC and thymocytes than TBI+PBS mice on day 14 after irradiation (all P<0.05). On days 7 and 14 after irradiation, TBI+IL-22 mice had higher counts of circulatory white blood cells and T cells than TBI+PBS mice (all P<0.05).@*Conclusion@#Sub-lethal TBI induces upregulation of intra-thymic IL-22, and injecting of recombinant IL-22 increases level of IL-22 in thymus. Injecting of recombinant IL-22 improves recovery of TEC and increases numbers of thymocyte subsets and circulatory T cell after thymic injury.
ABSTRACT
Objective: To explore the levels of IL-22 in thymus damaged by γ-ray total body irradiation (TBI), and to study the role of IL-22 in T cell reconstitution after thymic injury induced by TBI. Methods: To induce thymic injury, mice were treated by sub-lethal TBI. Levels of intra-thymic and circulatory IL-22 were detected by using ELISA assay. Untreated mice were used as control. After receiving sub-lethal TBI, mice were intraperitoneally injected with PBS or recombinant mouse IL-22, which were marked as TBI+PBS or TBI+IL-22, respectively. Mice were monitored for counts of total thymic cells and circulatory white blood cells. Flow cytometry was applied to analyze percentages of thymic epithelial cells (TEC), thymocyte subsets and circulatory T cells. Real-time PCR assay was applied to analyze the mRNA expression levels of Foxn1, Ccl25, Aire and Dll4 in thymus. Results: ①Sub-lethal TBI treated mice expressed higher levels of intra-thymic and circulatory IL-22, compared with untreated ones (all P<0.05). ②After injection of recombinant IL-22, TBI+IL-22 mice had higher levels of intra-thymic IL-22 than TBI+PBS mice (all P<0.05). ③On day 14 after irradiation, real-time PCR assay showed that TBI+IL-22 mice had higher mRNA levels of Foxn1, Ccl25, Aire and Dll4 in thymus compared with TBI+PBS ones. Meanwhile, the TBI+IL-22 mice had higher counts of total thymic cells[(5.93±3.19)×10(6)/ml vs (1.42±0.46)×10(6)/ml, t=3.128, P=0.033] and circulatory white blood cells[(3.08±0.94)×10(6)/ml vs (1.43±0.30)×10(6)/ml, t=3.730, P=0.015] than those of TBI+PBS mice. Flow cytometry analysis indicated that TBI+IL-22 mice had higher counts of TEC and thymocytes than TBI+PBS mice on day 14 after irradiation (all P<0.05). On days 7 and 14 after irradiation, TBI+IL-22 mice had higher counts of circulatory white blood cells and T cells than TBI+PBS mice (all P<0.05). Conclusion: Sub-lethal TBI induces upregulation of intra-thymic IL-22, and injecting of recombinant IL-22 increases level of IL-22 in thymus. Injecting of recombinant IL-22 improves recovery of TEC and increases numbers of thymocyte subsets and circulatory T cell after thymic injury.
Subject(s)
Animals , Mice , Interleukins , Radiation, Ionizing , T-Lymphocytes , Thymus Gland , Whole-Body Irradiation , Interleukin-22ABSTRACT
Objective To study the effects of thymus transplantation(TT)combined with CD4--DLI on T cell reconstitution after allogeneic hematopoietic stem cell transplantation(allo-HSCT). Methods BALB/c mice were randomly divided into three groups:hematopoietic stem cell transplantation (HSCT group),hematopoietic stem cell transplantation combined with thymus transplantation(TT group)and hematopoietic stem cell transplanta-tion combined with thymus transplantation plus CD4+ T cell-depleted lymphocyte infusion(CD4--DLI group). On day-1,the mice were treated with the lethal dose of radiotherapy. On day 0,C57BL/6 mice were used as donor for hematopoietic stem cell transplantation. The mice were sacrificed on 5 days,2 weeks,4 weeks and 3 months after transplantation,respectively. The peripheral blood and spleen cells of mice were collected for determinations of T cell surface antigen,T cell receptor,naive T cells and intracellular cytokines. HE staining was used to assess the development of donor thymus. Results TT and CD4--DLI did not impair each other′s effects on T cell reconstitu-tion. TT combined with CD4--DLI increased the number of T cell reconstruction. CD4--DLI promoted the effect of TT on enlargement naive CD4+and CD8+T cell pool. Combination of TT and CD4--DLI enhanced the cytokine pro-duction of T cells. Conclusion TT combined with CD4--DLI had no side effects on TCR repertoire and thymus. Conclusion TT combined with CD4--DLI can enhance the reconstitution of T cell number and function via thymus dependent and thymus independent mechanism.