Nano-silicon Dioxide Affects Apoptosis of Alveolar Macrophages via PI3K/AKt Signaling Pathway

Abstract

To investigate the effect of phosphatidyl inositol 3-kinase/protein kinase B (PI3K/AKt) signaling pathway on the apoptosis of alveolar macrophages (AM) induced by nano-silica (NS) dust. After exposure to different concentrations of NS suspension, CCK-8 assay was used to detect the AM viability; the cellular morphology of apoptotic AM was observed under fluorescence microscopy; the apoptosis rate and mitochondrial transmembrane potential of cells were detected by flow cytometry before and after pretreatment with phosphatidyl inositol 3-kinase (PI3K) inhibitor LY294002; Western blot was used to detect the expression of apoptosis-related proteins Bax, Bcl-2, p-PI3K and p-AKt. The survival rate of AM was decreased in a time-dose relationship after NS exposure. With LY294002 pretreatment, the mitochondrial transmembrane potential level and the expressions of p-PI3K, p-AKt and Bcl-2 were decreased, the expression of Bax and the apoptosis rate were increased. Our data suggested that the activation of PI3K/AKt signaling pathway played an important role in NS-induced apoptosis in alveolar macrophages.