Figure legends
Figure 1. Effects of empagliflozin and IL-1β on cell viability and chondrocyte phenotype maintenance of mouse chondrocytes. (A) CCK-8 analysis, *p<0.05 versus the IL-1β group. (C) Gross view of safranine O stained mouse chondrocytes that treated with empagliflozin at various concentrations (0, 1, and 5 μM) with or without IL-1β (10 ng/ml) for 24 h.
Figure 2. Effects of empagliflozin on IL-1β-induced ECM degradation in mouse chondrocytes. Chondrocytes were pretreated with empagliflozin at various concentrations (0, 1, and 5 μM) for 2 h and then incubated with IL-1β (10 ng/ml) for 24 h. (A) ELISA analysis of MMP9 and MMP13 in treated cells. (B) The mRNA expression levels of MMP9 and MMP13 in treated cells. (C) The protein expression levels of MMP9 and MMP13 in treated cells. *p<0.05 versus control group, #p<0.05 versus model group.
Figure 3. Effects of empagliflozin on IL-1β-induced inflammation in mouse chondrocytes. Chondrocytes were pretreated with empagliflozin at various concentrations (0, 1, and 5 μM) for 2 h and then incubated with IL-1β (10 ng/ml) for 24 h. (A) Nitrite production, PGE2 secretion, and IL-6 secretion in treated cells. (B) The mRNA expression levels of COX2 and INOS in treated cells. (C) The protein expression levels of COX2 and INOS in treated cells. GAPDH as an internal control. *p<0.05 versus control group, #p<0.05 versus model group.
Figure 4. Effects of empagliflozin on IL-1β-induced senescence in mouse chondrocytes. Chondrocytes were pretreated with empagliflozin at various concentrations (0, 1, and 5 μM) for 2 h and then incubated with IL-1β (10 ng/ml) for 24 h. (A) The protein expression levels of P21 and P53 in treated cells. GAPDH as an internal control. (B) β-galactosidase staining results of treated cells. *p<0.05 versus control group, #p<0.05 versus model group. Bar = 50 μm
Figure 5. Effects of empagliflozin on the IL-1β-induced NF-κB pathway activation in mouse chondrocytes. Chondrocytes were pretreated with empagliflozin at various concentrations (0, 1, and 5 μM) for 2 h and then incubated with IL-1β (10 ng/ml) for 15 min. The protein expression levels of P-P65, P65, p-IκB, and IκB in treated cells. The ratio of p-P65 to P65 as well as the radio of p-IκB to IκB was calculated. GAPDH as an internal control. *p<0.05 versus control group, #p<0.05 versus model group.
Figure 6. Effects of empagliflozin on cartilage degeneration in mouse OA model. (A) Microscopic images of safranin O stained mouse knee joint sections. Bar = 500 μm. (B) The OARSI grades. *p<0.05 versus control group, #p<0.05 versus model group.