Bone marrow-derived mesenchymal stem cells attenuate myocardial ischemia–reperfusion injury via upregulation of splenic regulatory T cells

Background Myocardial ischemia–reperfusion injury (MIRI) is the main pathological manifestation of cardiovascular diseases such as myocardial infarction. The potential therapeutic effects of bone marrow-derived mesenchymal stem cells (BM-MSCs) and the participation of regulatory T cells (Tregs) in MIRI remains to be defined. Methods We used the experimental acute MIRI that was induced in mice by left ascending coronary ischemia, which were subsequently randomized to receive immunoglobulin G (IgG) or anti-CD25 antibody PC61 with or without intravenously injected BM-MSCs. The splenectomized mice underwent prior to experimental MIRI followed by intravenous administration of BM-MSCs. At 72 h post-MIRI, the hearts and spleens were harvested and subjected to cytometric and histologic analyses. Results CD25+Foxp3+ regulatory T cells were significantly elevated after MIRI in the hearts and spleens of mice receiving IgG + BM-MSCs and PC61 + BM-MSCs compared to the respective control mice (all p < 0.01). This was accompanied by upregulation of interleukin 10 and transforming growth factor β1 and downregulation of creatinine kinase and lactate dehydrogenase in the serum. The post-MIRI mice receiving BM-MSCs showed attenuated inflammation and cellular apoptosis in the heart. Meanwhile, splenectomy compromised all therapeutic effects of BM-MSCs. Conclusion Administration of BM-MSCs effectively alleviates MIRI in mice through inducing Treg activation, particularly in the spleen.