Tannin Mediates the Secretion of Neutrophil Chemotactic Factor from Alveolar Macrophages in Rabbits and Humans

U. Specks, T.J. Kreofsky, A.H. Limper, W.M. Brutinel, and M.S. Rohrbach


 
ABSTRACT

Tannin inhalation causes acute neutrophilic alveolitis mediated by accumulation of a lipid neutrophil chemotactic factor (NCF) in the airways. In the rabbit model tannin promotes NCF secretion from alveolar macrophages (AM ) in a time and dose dependent manner. To assess the pertinence of the rabbit model in relation to pathogenetic mechanisms triggered by cotton dust inhalation in man, we compared tannin mediated NCF secretion by normal human AM in vitro to that by rabbit AM . NCF secretion from AM was tannin dose dependent both in the rabbit and in humans. The maximal effect was obtained at a tannin dose of 50 µg/mL in both. Whereas the maximal effect was reached after 5-6 hours of incubation of AM with tannin in the rabbit, the effect was maximal after 1 hour in humans. NCF secretion could not be inhibited by treatment of the AM with the 5-lipoxygenase inhibitor, nordihidroguaiaretic acid, either in the rabbit or in the human, indicating that the NCF secreted by tannin stimulated AM is not leukotriene B(4). As determined by gel-chromatography the NCF secreted by rabbit and human AM had a molecular weight of less than 800 dalton. The lipid nature of the NCF was demonstrated by ethyl acetate extraction. In conclusion, the data presented here indicate that tannin mediates NCF release from resident AM in rabbits and humans and thus may play an etiologic role in the acute neutrophilic alveolitis associated with cotton dust inhalation. They furthermore support the suitability of the rabbit model to study tannin mediated pathogenetic mechanisms operative in byssinosis.



Reprinted from Proceedings: 1989 Beltwide Cotton Dust Conference pp. 79 - 81
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998