Fig. 7
a Representative TUNEL staining of the lung tissue sections and (b) semi-quantitative measurement of apoptosis by counting TUNEL-positive cells. Positive staining is indicated in brown (arrow). The rats reared in hyperoxia and treated with NS or the surfactant exhibited significantly higher TUNEL-positive cells than did those reared in RA. Treatment with MSCs or MSCs + surfactant significantly reduced the hyperoxia-induced increase in TUNEL-positive cells. **P < 0.01 and ***P < 0.001. MSCs mesenchymal stem cells, NS normal saline, O 2 oxygen-enriched atmosphere, RA room air