Thymus regeneration following BMT with T-MSC co-transplantation. (A and B) Thymus size in experimental mice at sacrifice. Shown are thymuses on days 3, 10 and 40 following allogenic BMT with or without T-MSCs. (B and C) Hematoxylin and eosin staining of thymus tissue. Original magnification, ×40. (D) Histological tissue sections of thymuses collected from experimental mice on days 3, 10 and 40 post-BMT were stained with anti-CD3 antibody and hematoxylin dye (original magnification, ×200). (E) Quantification of CD3+ cells in thymus sections. One-way ANOVA followed by Sidak's multiple comparisons test; *P<0.05, **P<0.01, ***P<0.001 and ****P<0.0001 as indicated. BMT, one marrow transplantation; T-MSC, tonsil-derived mesenchymal stromal cell; Bu-Cy, busulfan-cyclophosphamide.