Fig. 3
From: Metformin attenuates silica-induced pulmonary fibrosis via AMPK signaling
Metformin attenuates SiO2-induced cell cytotoxicity. A, B, D and E Cell viability was detected by cck8 assay in HBE and A549 cells. HBE (A) and A549 (D) cells were treated for 24 h in different concentrations of SiO2 (0–200 μg/ml). HBE (B) and A549 (E) cells were cultured with 200 μg/ml SiO2 for 12, 24, and 48 h separately. C and F HBE (C) and A549 (F) cells were incubated with 200 μg/ml SiO2 for 24 h with or without metformin (2–10 mM/ml). After that, the cell viability was analyzed by cck8 assay. G The mitochondrial membrane potential of A549 cells was measured by JC-1 staining. CCCP, the positive control; Green fluorescence, the monomer; red fluorescence, the J-aggregates; scale bar = 50 μm. H LDH activity of the A549 and HBE cells was measured using LDH assay, with **p < 0.01 vs. silica group