The p-JNK signaling pathway contributes to KN93-induced apoptosis. (a, b) Apoptosis was observed in the control group, KN93 group, and KN93 + sp600125 group of PC12 cells using flow cytometry. ∗p < 0.05, compared with the control group. (c, d) Representative protein bands and analysis of data for caspase-3, Bcl-2, Bax, and cytochrome c in control groups, KN93 groups, and KN93 + sp600125 groups of PC12 cells and primary hippocampal neurons. ∗p < 0.05, compared with the control group; ∗∗p < 0.01, compared with the control group; ∗∗∗p < 0.001, compared with the control group; #p < 0.05, compared with the KN93 group.