TGFB1 and pulmonary fibrosis: The duration of the study was also chosen based on several previous studies reporting increased tracheal responsiveness to methacholine, cell count, interleukin 17 (IL-17), TGF-β levels in the BALF, and collagen deposition in the lung 15 days following PQ administration in mice26, induced lung pathological changes 28 days after PQ administration in Wistar rats27, and increased W/D of lung weight ratio, lung fibrosis as well as diminished arterial oxygen partial pressure, 7, 14, 21, and 28 days following PQ administration28.