Gas chromatographic-mass spectrometric analysis of lipoxygenase products in post-ischemic rabbit myocardium.
Leukotriene B4 (LTB4) is a potent chemotactic compound for neutrophils and is thought to be an important mediator of myocardial ischemia-reflow injury. We have measured LTB4 in rabbit cardiac tissue following ischemia-reflow using a sensitive and specific gas chromatographic-mass spectrometric (GC-MS) assay. The concentration of LTB4 in rabbit myocardium following 45 min ischemia and 3 h reflow was 48.7 +/- 12.5 pg/g, significantly higher than in non-ischemic tissue from the same animal (17.5 +/- 3.9 pg/g). These concentrations were at least an order of magnitude lower than previously reported values assessed by radioimmunoassay (RIA). Compared with the GC-MS method, RIA greatly overestimated LTB4 concentrations in cardiac tissue. The capacity of post-ischemic myocardium to produce lipoxygenase products, LTB4, 5-, 12- and 15-HETEs was also assessed following incubation of myocardium ex vivo with calcium ionophore. In all animals ischemic cardiac tissue produced greater amounts of LTB4, 5-, and 12-HETEs than non-ischemic myocardium and 12-HETE was the major product. Neutrophils that have accumulated in the injured tissue may be a major source of these products. However, in contrast to cardiac tissue, isolated rabbit neutrophils stimulated with A23187 produced 5-HETE as the major product with very little 12-HETE formed. These latter findings suggest that cells other than neutrophils may contribute to the production of lipoxygenase products during myocardial ischemia-reflow injury.
Hughes
H
H
Center for Experimental Therapeutics, Baylor College of Medicine, Houston, Texas 77030.
Gentry
D L
DL
McGuire
G M
GM
Taylor
A A
AA
D000818:Animals; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis* / Q000302:isolation & purification; D066298:In Vitro Techniques; D007700:Kinetics; D007975:Leukotriene B4 / Q000096:biosynthesis* / Q000302:isolation & purification; D008084:Lipoxygenase / Q000378:metabolism*; D008297:Male; D015425:Myocardial Reperfusion; D015428:Myocardial Reperfusion Injury / Q000201:enzymology*; D009206:Myocardium / Q000201:enzymology*; D011817:Rabbits; D011863:Radioimmunoassay / Q000379:methods; D013997:Time Factors
D006893:Hydroxyeicosatetraenoic Acids; D007975:Leukotriene B4; D008084:Lipoxygenase