RESUMEN
<p><b>OBJECTIVE</b>To investigate the effect of transplantation of bone-marrow mesenchymal stem cells (MSCs) on the immune functions of aging rats.</p><p><b>METHODS</b>Healthy SD rats were randomized into normal control, aging model group and MSCs group. The aging model was established by daily subcutaneous injection of D-galactose for 4 consecutive months. MSCs were isolated from the bone marrow of adult SD rats and injected (3×10(6) MSCs) in rats in the MSCs group via the tail vein once a week for 4 weeks. The spleen index, activity of T lymphocytes and the levels of IL-2 and IL-10 in spleen were measured, and the pathological changes of the spleen were observed after the treatments.</p><p><b>RESULTS</b>MSCs transplantation enhanced the cellular immune function of aging rats manifested by obviously increased spleen index, activity of T lymphocyte and the level of IL-2, and lowered level of IL-10 in the spleen. The rats in the aging model group showed serious spleen injury, which was obviously lessened by MSCs injection.</p><p><b>CONCLUSION</b>MSCs transplantation can improve the cellular immune function of aging rats and ameliorate spleen injury induced by D-galactose.</p>