Fig. 4
Cell viability and apoptosis of HBE cells after exposure to Al2O3 NPs. a Cell viability of HBE cells were analyzed through CCK-8 assays after exposure to Al2O3 NPs. b Apoptosis induction was significantly enhanced by Al2O3 NP exposure, and the proportion of necrosis was not significantly modulated c) Assessments of caspase-3, -8, and -9 activities in HBE cells and lung tissues harvested from mice treated with Al2O3 NPs. The increase of caspase-9 and -3 suggested that Al2O3 NPs induced apoptosis in HBE are mitochondria involved. * P < 0.05, compared with untreated control