A quantitative analysis of hematopoietic recovery modulated by MnSOD-PL. (a) The schematic design of the competitive BM transplant experiment and a representative flow cytometry analysis of competitive engraftment. Peripheral blood engraftment of transplant cells was examined by flow cytometry at (b) 3, 8, 12 and (c) 24 weeks after transplantation. Vector, mice received empty vector 24 hours before TBI; Pre-TBI, mice received MnSOD-PL intravenously 24 hours before TBI; Post-TBI, mice received MnSOD-PL intravenously immediately after TBI; Co-Tx, mice received MnSOD-PL with the transplanted BM cells; Post-Tx, mice received MnSOD-PL 24 hours after transplantation; Multi-inj., mice received MnSOD-PL at all time points mentioned above (n = 10 per group). (d) BM engraftment levels of the transplanted cells at 24 weeks after transplantation (n = 3–7 per group). (e) HSC frequencies in BM (n = 3–7 per group). (f) Peripheral blood engraftment following secondary transplantation (*P < 0.05; **P < 0.01; ***P < 0.001). BM, bone marrow; HSC, hematopoietic stem cell; MnSOD-PL, manganese superoxide dismutase-plasmid and lipofectin complex; TBI, total body irradiation.