RESUMEN
BACKGROUND:For autoimmune diseases, it is difficult to effectively solve the lack of immunological tolerance in patients by traditional treatments. Mesenchymal stem cells have the biological functions of tissue and organ regeneration and immune regulation. OBJECTIVE:To explore the effects and mechanisms of human umbilical cord-derived mesenchymal stem cells on the development of thymus in nude mice. METHODS:Human umbilical cord-derived mesenchymal stem cells were intraperitoneal y injected into BABL/c nude mice at a dose of 2×106 per mouse. We analyzed the maturation and distribution of thymic epithelial cells in the thymus rudiment of nude mice and the thymopoiesis of this newly developed thymus rudiment;furthermore, we explored the therapeutic effects of human umbilical cord-derived mesenchymal stem cells. RESULTS AND CONCLUSION:Our data showed wel-organized cortex-medul a structure and an obvious improvement in the maturation of thymic epithelial cells in the rudiment. We further demonstrated the improved thymopoiesis and the enhanced export of mature T cells with the T regulatory cells increase in peripheral blood. Furthermore, we found that human umbilical cord-derived mesenchymal stem cells could be engrafted in the thymus and express many cytokines, especial y keratinocyte growth factor which is essential for the thymus development. These findings indicate that a new mechanism of human umbilical cord-derived mesenchymal stem cells can provide a proper microenvironment for the reconstitution and functional maturation of thymus in nude mice, and elicit another insight in terms of therapeutic efficacy of human umbilical cord-derived mesenchymal stem cells in many autoimmune diseases.