In vitro and in vivo assessment of the pulmonary toxicity of cellulose.

The lung-damaging effect of intratracheally administered cellulose was studied by biochemical and histological methods. Cell count, protein, phospholipid, lactate dehydrogenase and acid phosphatase were determined in bronchoalveolar lavage fluid 1, 3 and 7 days after intratracheal instillation. Histological tests were performed after days 1, 3 and 30. In vitro, cellulose did not damage the macrophage cells. In vivo, interstitial oedema as well as the initial signs of inflammation could be detected in the lung after the first day. Inflammation after 1 week could be noted, partly interstitial and partly intra-alveolar and intrabronchial. In the bronchoalveolar lavage fluid, protein, lactate dehydrogenase, acid phosphatase, phospholipid and cell count were enhanced after days 1 and 3. After 1 month, the developing bronchioalveolitis is fibrous in character. Contrary to the in vivo study, cellulose did not damage rat peritoneal macrophages.