Induction of lung fibrosis in the mouse by intratracheal instillation of fluorescein isothiocyanate is not T-cell-dependent

Pulmonary fibrosis is the pathological result of a diverse group of insults. Common features of this group of diseases include chronic inflammation and immune cell activation. The pathogenesis of pulmonary fibrosis is not well defined and the prognosis is poor, highlighting the need for good animal models to elucidate the cellular and molecular events that lead to pulmonary fibrosis. This paper provides insight on a newly described model of pulmonary fibrosis using a single intratracheal challenge with fluorescein isothiocyanate (FITC). Balb-c and C57BL6 mice given intratracheal FITC develop acute lung injury followed by chronic inflammation. Significant increases in lung collagen content compared to saline-treated mice are noted at day 21 after inoculation. T-cell-deficient animals develop similar increases in lung collagen content compared to immunocompetent controls despite the abrogation of specific anti-FITC serum antibodies. Thus, the induction of fibrosis in FITC-challenged mice is not dependent on T cell immunity. Persistent chronic inflammation and acute lung injury may be the inciting events for the development of lung fibrosis in this model.