Fig. 4

Daphnoretin alleviated IL-1β-mediated chondrocyte apoptosis by abating ERS. 10 ng/mL IL-1β was applied to mediate chondrocyte apoptosis, and then 4 μM daphnoretin and/or 1 nM 4-PBA were administered on this basis. A The expression of GRP78, CHOP, ATF6, and Caspase-12 was compared by WB. B, C Flow cytometry was implemented to determine apoptosis. D WB was conducted to verify the profiles of Bax, Caspase-3, and Bcl2. E The Caspase-3 cell activity detection kit was adopted to test the Caspase-3 activity. *P < 0.05, **P < 0.01, ***P < 0.001 (vs. con group). &P < 0.05, &&P < 0.01, &&&P < 0.001 (vs. IL-1β group). nsP > 0.05 (vs.IL-1β + 4-PBA group). N = 3