Research Paper Volume 15, Issue 10 pp 4429—4443

Figure 1. Metformin inhibits LPS-induced KGN cell pyroptosis. (A, B) Cells were incubated with different concentrations of metformin (0, 5, 10, 20, 40 μM) for 12 h or 20 μM metformin for various periods (0, 6, 12, 24, 48 h). Then, an MTT assay was conducted to assess cell viability. (C–H) Cells were pretreated with or without 10 μM LPS for 24 h and then incubated with 20 μM metformin for another 12 h; (C) Quantification of mRNA expression of NLRP3, caspase-1, ASC, and GSDMD using RT-PCR; (D) Western blot analyses of NLRP3, pro-caspase-1, cleaved-caspase-1, ASC, and GSDMD-N; (E) Representative micrographs of PI staining (red) and Hoechst 33342 staining (blue); (F) Levels of LDH released into the cell culture medium from membrane pores were examined using an LDH cytotoxicity detection kit; (G) Caspase-1 activity was assessed using a colorimetric caspase-1 activity assay kit; (H) The levels of IL-1β, IL-18, IL-6, and TNF-α in the cell culture supernatant were determined by ELISA. Data are represented as the means ± SD from three independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, ns. not significant.