Metformin inhibits the proliferation of NIH 3T3 cells by activating AMPK. (A) The CCK8 test was applied to assess NIH 3T3 cells treated with metformin at various doses for 24 h. (B,C) Cell proliferation analysis by EdU incorporation assay. Transfected with siAMPK for 24 h, the cell proliferation ability of NIH 3T3 cells was measured by EdU assay. The percentages of EdU−positive cells are quantified in the bar graph. All data are expressed as the means ± SDs of values from triplicate experiments. * p < 0.05, ** p < 0.01, and *** p < 0.001. Blank: NIH 3T3 cells, siNC: siAMPK negative control group, siAMPK: NIH 3T3 cells transfected with si−Prkaa1−mus−1337.