Figure 3.

SiNPs activate autophagy and enhance autophagosome accumulation in the L-02 cells. (a) TEM images show that the autophagosomes accumulated in the L-02 cells with 25 μg/ml SiNPs treatment for 24 h. Red arrow, double-membrane autophagosome or single-membrane autolysosome. N, nucleus.Scale bars, 0.2 μm and 1 μm. (b) LSCM images of indirect immunofluorescence analysis show the LC3B distribution patterns in the control and SiNP-treated cells. LC3B (green) and DAPI staining of nuclei (blue) is shown. Scale bar: 25 μm. The number of punctate LC3B per cell in the untreated control and SiNP-treated cells is shown. Data are expressed as mean ± SD. *· p · 0.05 versus the control. (c) The L-02 cells were treated with 12.5, 25, and 50 μg/ml of SiNPs for 24 h. (d) The L-02 cells were pretreated with (+) or without (–) 10 nM BafA1 for 2 h, then the cells were treated with 12.5, 25, and 50 μg/ml of SiNPs for another 24 h. Thereafter, (c) and (d) cells were harvested and the expressions of LC3B and SQSTM1 were analyzed by western blot. Blots are representative of 3 independent experiments. ACTB was used as the sample-loading control. Densitometric LC3B-II:ACTB and SQSTM1:ACTB ratios from at least 3 independent experiments are shown. The value of the control without any treatment was set at 1 for each experiment (*, p < 0.05; N.S., not significant).