Figure 3.

Morroniside blocks H₂O₂-induced apoptosis of SK-N-SH cells. Apoptotic nuclei were visualized by Hoechst 33342 staining. (A) Untreated cells with normal nuclei. (B) Cells exposed to 200 µM H₂O₂ with condensed nuclei. (C–E) Cells pretreated with morroniside at concentrations of (C) 1 µM, (D) 10 µM and (E) 100 µM for 24 h showed reduced sensitivity to the effects of H₂O₂, as evidenced by fewer cells with condensed nuclei. Scale bar, 20 µM. (G–K) Annexin V/propidium iodide (PI) double-staining was used to confirm apoptosis in SK-N-SH cells. Few cells positive for Annexin V/PI staining were detected in the control group (G), while H₂O₂ (200 µM) treatment increased the percentage of Annexin V⁺/PI⁺ cells (H). Preincubation with (I) 1 µM, (J) 10 µM and (K) 100 µM morroniside for 24 h inhibited H₂O₂-induced apoptosis. Quantitative analyses are shown in panels (F and L). Data represent mean ± SD of three independent experiments. ^###P<0.001 vs. control group; ^*P<0.01, ^**P<0.01 and ^***P<0.001 vs. injury group.