Figure 2. Modulation of PGE₂ signaling increases survival and hematopoietic recovery post-irradiation.

a) Schema of the dosing strategies used post-irradiation, where dmPGE₂ was given as a single injection 6 hours post-irradiation, non-staggered Meloxicam was given as 4 injections starting at 6 hours post-irradiation, or 2 day staggered Meloxicam was given as 4 daily injections starting at 48 hours post-irradiation. b) Mice were irradiated with 796 cGys and treated with dmPGE₂ 6 hrs post-irradiation, 4 days of Meloxicam starting either 6 hours (no stagger) or 48 hours (2 day stagger) post-irradiation, or vehicle control and morbidity/mortality monitored for 30 days. N=20–40 mice per group. *P<0.05. c) In a separate experiment, irradiated mice were treated with a single dose of dmPGE₂ 24 hours post-irradiation and morbidity/mortality was monitored for 30 days compared to vehicle control. N=20 mice per group. *P<0.05. Blood recovery of d) white blood cells (WBC), e) polymorphonuclear leukocytes (PMN) and f) platelets (PLT) post-irradiation. g) Kinetic analysis of hematopoietic progenitor function post-irradiation as measured by colony forming cell (CFC) assay in dmPGE₂ or vehicle treated mice, with comparison to non-irradiated controls. N=3 mice per group per time point, each assayed individually. *P<0.05.