Fig. 5

Temporality of synergistic sim-µG + IR effects observed on endothelial nitric oxide (NO) synthase (eNOS) immunoreactivity. Mice were hindlimb unloaded for 14 days with whole-body proton-IR (50 cGy, 150 MeV) on day 7. eNOS immunoreactivity in rodents was assessed following (A) 4 days or (B) 30 days of recovery from control or spaceflight-analog conditions of irradiation (IR), simulated microgravity (Sim-µG), or combined Sim-µG + IR.  (C) eNOS immunoreactivity was slightly increased in only the combined sim-µG + IR exposure cohort after four days of re-adaptation. This was further significantly and synergistically increased thirty days after exposure. These results reinforce the dynamic temporal interplay between sim-µG and IR, both during and post-spaceflight [91]. Data shown are mean density of eNOS-positive endothelial cells ± standard error of the mean (SEM) (n = 8/group). Figures re-created and modified from [91] with express permission from the publisher