The effects of the transplantation of thymus-derived multipotent stromal cells on the immune system and survival of lethally irradiated mice

Abstract

The traditional source for regeneration of the immune system is hematopoietic stem cells. Multipotent stromal cells (MSCs), especially MSCs of the thymus, have been significantly less studied for this purpose.The aim was to study the regenerative, immunobiological and radioprotective properties of thymus-derived multipotent stromal cells.Materials and methods. Researches were conducted to study the effect of transplantation of thymus-derived MSCs on the survival and features of restoration of the immune system of lethally irradiated mice. Lethally irradiated (with dose 9 Gy) CBA mice, 5-6 weeks old, were injected intravenously with 5·104 thymus-derived MSCs. On the 30th day the cellularity of lymphoid organs, bone marrow and blood, natural and adaptive immunity were studied.Results. It was found that transplanted thymus-derived MSCs significantly prolonged the survival and average lifespan of mice, restored the cellularity of bone marrow, the ability of bone marrow stromal cells to form fibroblast colonies, greatly increased the cellularity of the thymus and contributed to the normalization of the number of leukocytes in the blood. In addition, the natural cytotoxic activity of splenocytes and their ability to synthesize α/β- and γ-interferons, significantly increased, the number of antibody-producing cells was stimulated and the synthesis of antibodies increased. The concentration of the tumor necrosis factor α in the blood was significantly reduced.Conclusions. The results indicate that thymus-derived MSCs possess pronounced regenerative and immunobiological activity, which provides these cells with radioprotective ability. The obtained data can be used to develop combined cell transplants and new methods for improving their regenerative potential and radioprotective effects.