Radioprotection of mouse hematopoietic stem cells by leukotriene A4 and lipoxin B4.

Abstract

The potent cyto/radioprotective biological activity induced by leukotrienes prompted a search for other lipoxygenase products exhibiting similar properties. Pretreatment of mice with 1 to 20 μg of leukotriene A₄ before sublethal irradiation induced an increase in the number of endogenous hematopoietic stem cells. Radioprotection was also provided by pretreatment with lipoxin B₄, but not with lipoxin A₄ or with potential lipoxin precursors: 5-HETE, 15-HPETE, 15-HETE, and arachidonic acid. The degree of protection induced by leukotriene A₄ or lipoxin B₄ is less than that previously reported for an equivalent dose of leukotriene C₄. Administration of the lipoxins did not result in any visibly detectable side effects such as diarrhea or ataxia.