Due to the importance of alveolar macrophages (AM) in pulmonary defense mechanisms, studies were performed in order to evaluate the activity of these cells. Bronchoalveolar lavages (BAL) were obtained from five healthy horses, and cytology was performed on glass slides after cytocentrifugation of the samples. Slides were stained by Rosenfeld. All BAL samples were centrifuged and cell concentration was adjusted to 2×10(6) cells/ml, for the measurement of AM activity (spreading, phagocytosis and hydrogen peroxide release tests). Differential counting of the BAL cells demonstrated that macrophages were the predominant type of cell (59.0± 6.9%). Measurement of AM activity presented the following results: spreading rate, 25.1± 19.7%, phagocytosis rate, 89.4± 6.2% and hydrogen peroxide release, 1.6± 0.3nmoles/2×10(5) cells (without PMA- phorbol 12-myristate 13-acetate) and 1.8± 0.4nmoles/2×10(5) cells (with PMA). Results presented a pattern for the activity of AM in healthy horses enabling the demonstration of an activation rate even without known previous eliciting factors. These results indicate that the tests of macrophage activity measurement are adequate for evaluation of phagocytic activity of AMs.
Horse; alveolar macrophage; phagocytosis; bronchoalveolar lavage
