Dieckol rescues mice from lethal irradiation by accelerating hemopoiesis and curtailing immunosuppression.

To evaluate the radioprotective effect of dieckol, a component of the brown algae Ecklonia cava.Mice were lethally irradiated, treated with dieckol and surveyed for survival and the mechanism of radioprotection.Dieckol treatment lengthened the survival of irradiated mice and significantly accelerated the hemopoietic recovery of bone marrow cells and peripheral immune cells compared with irradiated, but untreated controls. Dieckol also enhanced the proliferation and differentiation of immune cells, which had been suppressed by ionising radiation. It turned out that the increased expression of oxygen radical-scavenging enzyme manganese superoxide dismutase (MnSOD) and subsequent reduction in DNA damage and lipid peroxidation was crucial for dieckol's radioprotective effect. In addition, the dieckol-induced modulation of protein 53 (p53)-dependent pathways further strengthened the radioresistance of immune cells.Dieckol can be a promising agent for reducing the time needed for reconstitution of hemopoietic cells after exposure to irradiation.