Figure 6. Metformin inhibited cell senescence of rabbit AF cells induced by LPS tested by b-gal staining. (A, E) the cells were cultured with normal medium (control). (B, F) the cells were cultured with 100 ng/ml of LPS-containing medium (LPS). (C, G) the cells were cultured with 1 mM of metformin-containing medium (Met). (D, H) the cells were cultured with 100 ng/ml of LPS and 1 mM of metformin (LPS+Met). The images of (E–H) were enlarged images of the box areas of the images of (A–D) LPS induced more than 77% of rabbit AF cells to senescence as evidenced by b-gal staining (green cells in B, F). Metformin inhibited cell senescence induced by LPS (D, H), (I) semi-quantification of positive stained cells by b-gal. *p<0.05 compared to the control group. #p<0.05 compared to the cells treated with LPS. White bars = 100 μm, yellow bars = 25 μm.