Lung-Cpr-null mice and their WT control littermates, both male and female, were compared on C57BL/6 genetic background for extents of PQ-induced lung fibrosis (sizes of lung areas with collagen fibril deposition detected on picrosirius red-stained tissue sections and levels of mature collagens in lung tissue homogenate). The gene discussed is POR; the disease is pulmonary fibrosis.