The early effects of chrysotile asbestos dust on the rat lung

Asbestos bodies in rat lung following intratracheal instillation of chrysotile

“…These fibrotic areas either were focal and specifically associated with bronchiolar walls (often with accumulated macrophages and occasionally involving a local proliferation of bronchiolar or alveolar duct smooth muscle cells) or were more diffusely structured and parenchymal, resembling small chronic inflammatory lesions. Similar lesions have been described in rats exposed to chrysotile in previous experimental studies of asbestosis (Holt et al, 1964;Gross & De Treville, 1967;Lemaire et al, 1985). They were similar also to the small-airway lesions in asbestosexposed human lungs described by Wright and Churg (1984).…”

“…Thus Holmes and Morgan (1980) and Botham and Holt (1972b), for example, have described 'rare and atypical' asbestos bodies in rat lung following inhalation of anthophyllite and crocidolite, but with regard to experiments using chrysotile there is only one known report of asbestos bodies being found in rat lung (Vorwald, Durkan & Pratt, 1951). Holt, Mills and Young (1964) found no bodies after long-term inhalation of chrysotile dust by rats, and similarly none was found by Wagner et af. (1974) in a series of detailed experiments on the effects of inhalation of all four main asbestos types (chrysotile, crocidolite, amosite and anthophyllite).…”

Sequence of bronchoalveolar lavage and histopathologic findings in rat lungs early in inhalation asbestos exposure

“…The concentration of asbestos used in this experiment, when inhaled daily for 3 mo or longer, is known to cause fibrosis in rat lungs (Wagner et al, 1974;Holt et al, 1964;Tetley et al, 1976;Davis et al, 1978;Barry et al, 1983;Wagner et al, 1980). Using the same dose for shorter exposure periods of 2, 4, and 6 wk revealed (1) a demonstrable inflammatory and fibrotic process in the terminal airways after 2 wk of exposure (Figs.…”

“…In previous inhalation experiments, the time periods studied have been either very brief (1 h) (Brody et al, 1981) or very long after fibrosis is already evident (3 mo or longer) (Wagner et al, 1974(Wagner et al, ,1980Holt et al, 1964;Tetley et al, 1976;Davis et al, 1978;Barry et al, 1983). In these time periods, increases only in the number of macrophages have been uniformly observed.…”

Minerals, Fibrosis, and the Lung

“…The inability ofVorwald et al (130) to obtain a significant reaction to short (ballmilled) chrysotile occasions no surprise, since 98.6% of their dust was nonfibrous. It should also be recollected that pulmonary fibrosis was induced in rats and guinea pigs with ball-milled serpentine or amphibole fibers (137,138), which by electron microscopy were . 5 lm in length including many ofthe order of 1 itm (139).…”