Endogenous splenic colonies and megakaryopoiesis in methylcellulose treated irradiated mice

Endogenous splenic colonies are increased in methylcellulose-treated irradiated mice, 10 days after sublethal irradiation (450 R). The spleen shows an enhancement of megakaryopoiesis, especially localized around foam-cell foci. This suggests that the macrophage system, activated through phagocytic activity against methylcellulose, affects megakaryopoiesis by a microenvironmental mechanism.