Glucan: Mechanisms Involved in Its Radioprotective Effect
ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD
Pagination or Media Count:
It has generally been accepted that most biologically derived agents that are radioprotective in the hemopoietic-syndrome dose range eg, endotoxin, Bacillus Calmette Guerin, Corynebacterium parvum, etc exert their beneficial properties by enhancing hemopoietic recovery and hence, by regenerating the hosts ability to resist life-threatening opportunistic infections. However, using glucan as a hemopoietic stimulantradioprotectant, we have demonstrated the host resistance to opportunistic infection is enhanced in these mice even prior to the detection of significant hemopoietic regeneration. This early enhanced resistance microbial invasion in glucan-treated irradiated mice could be correlated with enhanced andor prolonged macrophage but not granulocyte function. These results suggest that early after irradiation glucan may mediate its radioprotection by enhancing resistance to microbial invasion via mechanisms not necessarily predicated on hemopoietic recovery. In addition, preliminary evidence suggests that glucan can also function as an effective free-radical scavenger. Because macrophages have been shown to selectively phagocytize and sequester glucan, the possibility that these specific cells may be protected by virtue of glucans scavenging ability is also suggested.
- Medicine and Medical Research