Fig. 5

Detection of apoptosis by TUNEL assay in intra-alveolar buds of granulation tissue. a Representative images of double immunofluorescence of TUNEL (green) and α-SMA (red) in normal lung and in lung studied at days 4, 7 and 14 after a single orotracheal instillation of gastric fluid. Cell nuclei are co-stained (blue) with DAPI (4′,6-diamidino-2-phenylindole). Apoptosis is executed in α-SMA –positive and –negative cells inside intra-alveolar buds at day 4 and more intensely at day 7 after gastric fluid instillation. Arrows indicate α-SMA-positive cells that are also positive for TUNEL. Arrowheads indicate α-SMA-negative cells that are TUNEL positive. Original magnification: 630×. b Quantitation of TUNEL positive cells in percentage of total cells in Masson bodies. *: p < 0.05; ***:p < 0.001 in comparison to controls. ND: non detectable