The immunocytochemical localization of tumour necrosis factor and leukotriene in the rat heart and lung during endotoxin shock.

After the intravenous administration of lipopolysaccharide at a dose of 3.0 mg/100 g to rats, immunoreactive sites for tumour necrosis factor (TNF) and peptide leukotrienes (LTs) were examined in the heart and lung. Immunoreaction for TNF is preferentially localized on the apical endothelial cell surface of the vessels and in lysosomes of inflammatory and interstitial cells. Lysosomes of cardiac muscle cells which undergo degeneration are also reactive. Peptide LTs in inflammatory cells give almost the same reactions as those for TNF. However, the production of peptide LTs occurs uniquely in cardiac muscle cells in the media of the pulmonary vein, although lysosomes of intracardiac muscle cells which undergo degeneration do not show immunoreactivity. These results suggest that the degeneration of cardiac muscle cells may be induced not only by endogenous TNF but also by peptide LTs which are produced in muscle cells of the venous media and are transported to the myocardium via the coronary circulation.