Effects of bone marrow mesenchymal stem cell transplantation on thymus structure and function in the aging macaques / 中国组织工程研究

ABSTRACT

BACKGROUND: Thymus is an important central immune organ of human body, which is the place where T cells grow, develop and mature. Thymus is the first organ of senescence in human body, gradually atrophy and degeneration after puberty, followed by the gradual decline of immune function. OBJECTIVE: To investigate the effect of bone marrow mesenchymal stem cells on the structure and function of thymus in the aging macaques. METHODS: Bone marrow was collected from female macaques with an average age of 3 years by bone marrow aspiration. Bone marrow mesenchymal stem cells were obtained by differential adherent culture. Five young macaques with an average age of 3 years were used as the young group. Ten aging macaques with an average age of 25 years were randomly divided into elderly group (n=4) and elderly treatment group (n=6). The macaques in the elderly treatment group were infused with bone marrow mesenchymal stem cells (1 × 107 cells/kg) through the femoral vein, and were infused every other day for three consecutive times. Macaques of the young group and the elderly group were infused with the same volume of saline at the same time. The changes of output and secretion levels of the subgroup of thymocytes in the elderly treatment group after infusion, thymic index, thymic tissue structure and collagen fiber deposition in each group were analyzed. RESULTS AND CONCLUSION: Bone marrow mesenchymal stem cell transplantation increased thymus index, T cell output level and reduced regulatory T cells, improved thymus secretion function, increased thymosin alpha and thymosin II secretion. The thymus parenchyma area increased; the skin and medulla junction appeared; part of the thymus tissue was regenerated and transformed to normal structure; the degree of thymus tissue fibrosis was reduced; and collagen fiber deposition was reduced. These results indicate that bone marrow mesenchymal stem cell transplantation can improve the structure and function of thymus in aging macaques.