Leukotriene-induced radioprotection of hematopoietic stem cells in mice.

Leukotrienes (LTs), known primarily for their pathological roles, may also be capable of exerting "cytoprotection" against toxic agents in a manner similar to that of prostaglandins. In this report, it is shown that treatment of mice with leukotrienes C4, D4, E4, or B4 prior to sublethal irradiation increased the number of endogenous hematopoietic stem cells (E-CFU), with LTC4 producing the greatest response (LTC4 much greater than B4 greater than E4 greater than D4). LTC4-induced hematopoietic radioprotection was examined in greater detail using the exogenous spleen colony (CFU-S) and granulocyte/macrophage progenitor cell (GM-CFC) assays. The dose reduction factors for these cells in LTC4-treated mice at radiation doses resulting in 37% cell survival were 1.65 and 2.01, respectively.