Sirius Red (collagen) stained lung sections showing the degree of accumulation of collagen fibers in lung tissue. Pulmonary fibrosis was induced by intra-tracheal instillation of bleomycin sulfate. The animals were treated with vehicle or low dose esomeprazole (prophylactic) for up to 28 days prior to harvesting and staining for collagen. Treatment with esomeprazole effectively prevented the accumulation of collagen compared to vehicle treatment as shown. Lower panel shows average lung fibrosis score of 10 animals per group. No bleomycin sham group was included as control. *p < 0.05 compared to vehicle. Representative images are shown.