Fig. 4

H₂S promotes megakaryocytes/platelets generation but does not improve survival in TPO^−/− mice. a Without radiation exposure, NaHS treatment (20 μmol kg⁻¹ day⁻¹) for 14 days caused an increase in circulating platelet levels in both WT and TPO^−/− mice. b NaHS treatment (100 μmol L⁻¹) increased the number of megakaryocytes identified as CD61-positive cells using flow cytometry in cultured fetal liver cells isolated from TPO^−/− mice. c, d NaHS treatment (100 μmol kg⁻¹ day⁻¹) increased circulating platelet levels on day 7 after radiation exposure in both WT and TPO^−/− mice (c). However, the effects of NaHS treatment (100 μmol kg⁻¹ day⁻¹) in increasing circulating platelet levels were blunted in TPO^−/−mice (d). e Morphological examination of the bone marrow showed that NaHS treatment (100 μmol kg⁻¹ day⁻¹) did not increase the number of megakaryocytes (black arrows) in the TPO^−/− mice exposed to radiation. Scale bar = 250 μm. f Bleeding was not ameliorated with NaHS treatment (100 μmol kg⁻¹ day⁻¹) in the TPO^−/− mice exposed to radiation at day 7. g Likewise, fecal occult blood was not ameliorated with NaHS treatment (100 μmol kg⁻¹ day⁻¹) in the TPO^−/− mice exposed to radiation at day 7. h Survival was not improved with NaHS treatment (100 μmol kg⁻¹ day⁻¹) in TPO^−/− mice exposed to radiation. **P < 0.01 versus vehicle-treated mice exposed to radiation, log-rank test. Data in the graphs are means ± SEM. P values less than 0.05 represent statistical significance