The time course of responses to intratracheally instilled toxic Stachybotrys chartarum spores in rats

Stachybotrys chartarum is a fungal species that can produce mycotoxins, spe cifically trichothecenes. Exposures in the indoor environment have reported ly induced neurogenic symptoms in adults and hemosiderosis in infants. Howe ver, little evidence has linked measured exposures to any fungal agent with any health outcome. We present here a study that focuses on quantitatively assessing the health risks from fungal toxin exposure. Male, 10 week old C harles River-Dawley rats were intratracheally instilled with approximately 9.6 million Stachybotrys chartarum spores in a saline suspension. The lungs were lavaged 0h (i.e., immediately post-instillation), 6, 24 or 72h after instillation. Biochemical indicators (albumin, myeloperoxidase, lactic dehy drogenase, hemoglobin) and leukocyte differentials in the bronchoalveolar l avage fluid and weight change were measured. We have demonstrated that a si ngle, acute pulmonary exposure to a large quantity of Stachybotrys chartaru m spores by intratracheal instillation causes severe injury detectable by b ronchoalveolar lavage. The primary effect appears to be cytotoxicity and in flammation with hemorrhage. There is a measurable effect as early as 6h aft er instillation, which may be attributable to mycotoxins in the fungal spor es. The time course of responses supports early release of some toxins, wit h the most severe effects occurring between 6 and 24h following exposure. B y 72h, recovery has begun, although macrophage concentrations remained elev ated.