Pulmonary fibrosis is a serious lung disorder that in certain cases may be difficult to quantify. It was our objective to evaluate the use of
laser scanning confocal microscopy (LSCM) in quantifying
fibrosis after exposure to
amiodarone (AD) and
bleomycin (BLM), two commonly used therapeutic drugs known to cause debilitating lung
fibrosis in humans. Male F344 rats were intratracheally dosed with AD (6.25 mg/kg on days 0 and 2), BLM (0.25 and 1.0 mg/kg on day 0), or their respective vehicle controls. The right lung was assayed for
hydroxyproline, a biochemical measure of
collagen, at day 21 for the BLM groups and day 28 for the AD groups. The left lung was fixed, sectioned into blocks, dehydrated, stained with
Lucifer yellow (LY, 0.1 mg/ml), and embedded in
Spurr resin. The area of lung tissue stained by LY was quantified by LSCM. A fibrotic response in the AD and BLM groups was confirmed by histopathological assessment and a significant increase (p < 0.05) in total right lung
hydroxyproline above control values. The area of connective tissue stained by LY of the two drug-treated groups appeared as bright linear bands in the alveolar septae and was significantly increased (p < 0.05) as measured by image analysis when compared with their respective controls. LSCM, with its advanced image analysis system, is an alternate method to quantify fibrotic
lung disease. LSCM could be particularly useful when tissue quantity is limited, such as when tissue has been archived from previous studies, or when analyzing human lung biopsy samples for disease diagnosis, where biochemical analysis is difficult.