Abstract: OBJECTIVE: To investigate the effect of p38 MAPK signaling pathway on the apoptosis induced by olaquindox in human hepatoma G2 (HepG2) cells. METHODS：The HepG2 cells were treated with different concentrations (0，200，400，800 μg/ml) of olaquindox for 24 h or with 800 μg/ml olaquindox for different time points (0，0.5，1，2，4，6，12，24 h). Then the expression of p38 and phosphorylation of p38 (p-p38) were determined by Western blot. The HepG2 cells which were pretreated with different concentrations (0，10，20 μmol/L) of SB203580 for 1 h were subsequently treated with 800 μg/ml olaquindox for 24 h. The changes of apoptosis were analyzed by Annexin V-FITC and propidium iodide (PI) staining. RESULTS：The expression of p-p38 increased gradually with the dose and time of olaquindox treatment. Moreover，compared with control group，the expression of p-p38 was observably apparent with the treatment of 800 μg/ml olaquindox for 24 h (P＜0.01). Compared with olaquindox control group (23.1%±3.59%)，the apoptosis of olaquindox-treated HepG2 cells was enhanced by different concentrations (10，20 μmol/L) of SB203580 with the apoptotic rate of 35.4%±2.83% and 40.2%±3.98% respectively (P＜0.05). CONCLUSION：p38 MAPK signaling pathway was activated by olaquindox，which played a role in inhibiting apoptosis induced by olaquindox-treated HepG2 cells.

Key words: Olaquindox, p38 MAPK, apoptosis, HepG2 cells