Abstract: Objective To observe the effect of oleanolic acid on senescent Leydig cells and the regulation of EGF and EGFR. Methods Primary cultured rat Leydig cells were divided into normal group, model group and oleanolic acid group. The model group and the neat fruit acid group were treated with H₂O₂(300 μmol/L)and FeSO₄(100 μmol/L)daily for 2 h for 4 d. Thereafter, the normal and model groups were cultured in DMEM/F12 medium for 3 d, and the oleanolic acid group was cultured in DMEM/F12 medium with a final concentration of 20 μmol/L. Testosterone secretion was measured by ELISA, proliferation by immunofluorescence staining by BrdU, apoptosis by DAPI staining, and EGF and EGFR mRNA expression by qRT-PCR. Results Compared with the normal group, the testosterone secretion level, cell proliferation rate, EGF and EGFR mRNA expression level were significantly decreased(P<0.05), and the apoptosis rate was significantly increased(P<0.05). Oleanolic acid significantly inhibited apoptosis in the model group(P<0.05)and significantly increased testosterone secretion, cell proliferation levels, and EGF and EGFR mRNA expression levels(P<0.05). Conclusion Oleanolic acid can promote testosterone secretion and cell proliferation and inhibit cell apoptosis, and its mechanism may be related to the regulation of EGF and EGFR mRNA expression.

Key words: Leydig cells, oleanolic acid, senescence, epidermal growth factor, epidermal growth factor receptor