Updated project metadata. Bleomycin-induced pulmonary fibrosis in mice mimics major hallmarks of idiopathic pulmonary fibrosis, yet in this model it spontaneously resolves over time. We studied molecular mechanisms of fibrosis resolution and lung repair, focusing on transcriptional and proteomic signatures and the effect of aging. Young (3 months) and old (21 months) mice were treated with Bleomycin or with control saline solution and analyzed transcript and protein expression over 8 weeks (Day 0, 14, 21, 28, 35, 42, 49, 56).