To study the time course of fibrosis development in a direct comparison with Bleomycin-induced lung injury, the most commonly used model of lung fibrosis, C57Bl/6 mice received either 2.5E + 11 vector genome-containing particles (vg) of single-stranded AAV6.2-CMV-TGFβ1 (AAV-TGFβ1) or 1 mg/kg Bleomycin by intratracheal (i.t.)administration. The gene discussed is TGFB1; the disease is pulmonary fibrosis.