Detection of hUC-MSC in lung tissue by vimentin IHC.

<p>Lung sections obtained from C57BL/6 mice (n = 8 per group) receiving endotracheal bleomycin only (<b>A</b>, <b>B</b>, <b>E</b>) or endotracheal bleomycin followed by intravenous hUC-MSC (<b>C</b>, <b>D</b>, <b>F</b>) were immunostained with anti-human vimentin antibody. (<b>C,D)</b> Lung sections from hUC-MSC-treated mice show at day 8 (i.e. one day after second hUC-MSC infusion) numerous immunoreactive cells, distributed mainly in the septa and in the peribronchial tissue (200X), that exhibit at higher magnification (400X) a polygonal or stellate shape and enlarged nuclei (arrows). (<b>A,B</b>) In lung sections from mice treated with bleomycin only, the anti-human vimentin staining is extracellular and unspecific; no cells with polygonal or stellate shape reactive for human vimentin are evident (200X and 400X). (<b>F</b>) Lung sections from hUC-MSC-treated mice show at day 21 (i.e. 14 days after second hUC-MSC infusion) normal alveolar architecture with no fibrosis or inflammation, which are evident in the untreated mice (<b>E</b>), and only few vimentin-positive cells (arrows).