Leukotriene B 4, polymorphonuclear leukocytes and inflammatory exudates in the rat

Abstract

Leukocyte numbers and Leukotriene B 4- (LTB 4-) and LTC 4-immunoreactivity were measured in inflammatory exudates obtained from sponges impregnated with several irritants implanted subcutaneously in the rat. Sponges containig 1% uric acid, carragennan or zymosan were implanted for 5h and compared to saline sponges. Increases in leukocyte numbers and LTB 4-immunoreactivity were found in the presence of irritants, the highest concentrations being observed in the presence of zymosan. The presence of LTB 4 was confirmed by liquid chromatographic (HPLC) analysis. A time course study was carried out with zymosan-impregnated sponges and the maximal rate of leukocyte infiltrations was found to coincide with the maximal levels of LTB 4-immunoreactivity. The LTC 4-immunoreactivity was low and following analysis by HPLC was concluded to be unrelated to leukotrienes. The levels of LTB 4-immunoreactivity, but not the numbers of leukocytes, were elevated compared to corresponding controls in sponges containing 0.01% ionphore A23187 (untreated rats) or in sponges containing zymosan (rats pretreated with indomethacin; 3 and 10 mg/kg p.o.). Impregnation of sponges with 3 × 10 −6M LTB 4 but not 3 × 10 −7M LTB 4 induced a significant leukocyte migration. It was concluded that LTB 4 can induced leukocyte migration into sponge exudates in the rat but that measurements of LTB 4 in such exudates can not be correlated with the degree of leukocyte infiltration.