Fig. 1

H₂S treatment promotes platelet generation, alleviates bleeding, and improves survival in WT mice with radiation-induced myelosuppression. a Time course of circulating platelet counts after exposure to radiation of ¹³⁷Cs at a single dose of 7.5 Gy. b NaHS treatment caused a significant increase in circulating platelet levels at 100 and 150 μmol kg⁻¹ day⁻¹ on day 7 after radiation exposure. TPO treatment also provided a similar amelioration at 15 μg kg⁻¹. c Morphological examination showed a significant decrease in the number of megakaryocytes (black arrow) in the bone marrow of WT mice exposed to radiation, whereas NaHS (100 μmol kg⁻¹ day⁻¹) significantly increased the number of megakaryocytes as compared with the vehicle-treated group. Scale bar = 250 μm. d Bleeding time was prolonged after exposure to radiation, and bleeding was ameliorated by NaHS treatment (100 μmol kg⁻¹ day⁻¹) as compared with that of vehicle-treated WT mice. e Likewise, fecal occult blood was significantly increased after exposure to radiation and NaHS treatment (100 μmol kg⁻¹ day⁻¹) caused a significant decrease in fecal occult blood in mice exposed to radiation. f Plasma TPO concentrations were increased in WT mice on day 7 after radiation exposure where NaHS treatment (100 μmol kg⁻¹ day⁻¹) did not change TPO concentrations. g Radiation exposure resulted in a significant decrease in survival as compared with that of the mice without radiation exposure. Both NaHS (100 μmol kg⁻¹ day⁻¹) and TPO (15 μg kg⁻¹) treatment significantly improved survival in these mice exposed to radiation. *P < 0.05, **P < 0.01 versus vehicle-treated mice exposed to radiation, log-rank test. h Plasma H₂S levels were decreased in mice exposed to radiation, and this decrease was recovered by administration of NaHS (100 μmol kg⁻¹ day⁻¹). Data in the graphs are means ± SEM. P values less than 0.05 represent statistical significance