Fig. 4.

BMSCs barely adopt alveolar cell phenotypes. a, b Quantified engraftment levels of BMSCs in the lungs by real-time PCR analysis. Sry, representing male BMSCs DNA, was only shown up in the silica + BMSCs group on day 15 (a), but did not show up on day 30 (b). The male rat lung served as the positive control. The data were presented as the means ± SD. **p < 0.01 versus the control group. c, d Immunofluorescence (IF) of the lung sections was tested on day 15 (c) and on day 30 (d) by using a confocal microscopy. Nuclear staining (DAPI, blue), BMSCs (RBMY, green), and the ATI cells (AQP-5, red). The level of AQP-5 (red) protein expression was reduced in the silica group, but increased after treatment with BMSCs. Little RBMY protein (green) was detected in the lung tissue from the silica + BMSCs group on day15, but not on day 30. Colocalization, indicated by a yellow color, was not observed in the merged panel in the silica + BMSCs group. Male rat lung served as the positive control. Scale bar = 250 μm. e, f Quantification of fluorescence intensity was analyzed in each group on days 15 (e) and 30 (f). Values are expressed as mean ± SD, n = 8. **p < 0.01 compared with the control group; ^##p < 0.01 compared with the silica group; ^&&p < 0.01 compared with the silica + BMSCs group