Résumé
Objective To investigate the role of the extracellular signal-regulated kinases 1 and 2 (ERK1/2) in rotenone-mediated dopaminergic cell damage. Methods Neuronal rat adrenal pheochromecytoma(PC12) cells treated with rotenone were used as the cell model of Parkinson' s disease (PD). Cell viability of PC12 cells after exposure to rotenone was detected by MTT (methyl thiazolyl tetrazolium) method. Immanohistechemistry was used to detect the phosphorylation of ERK1/2 in cells exposed to rotenone. Western blotting was used to verify the phosphorylation of ERK1/2 and to observe the effect of PD98059, an inhibitor of the upstream mitogen activated protein kinase kinase (MEK) that phosphorylates and activates ERK1/2, on rotenone-induced ERK1/2 phosphorylation and cell viability.Results The viability (represented by A570 of PC12 cells exposed to 5 μmoL/L rotenone) declined with the increase of exposure time from 1 h to 24 h (%, 1 h :75.46±5.47, 2 h : 70.42±1.94, 4 h : 65.23± 0.96, 8 h : 59.04 ± 2.85, 24 h :29.64 ± 1.63, comparison between different time points(F=143.014, P=0.000) ; compared with control groups(100.00±2.89), q value: 17.07, 20.58, 24. 19, 28.50, 48.95 respectively, all P <0.01). After exposure to rotenone, phosphorylated ERK1/2 aggregated in the PC12 cells. Western blotting indicated that rotenone induced a biphasic phosphorylation of ERK1/2, which increased from 30 min after rotenone treatment, reached the peak at 1-2 h, decreased at 4 h, and increased again at 8 h, and disappeared after 16 h; PD98059 significantly inhibited ERK1/2 phosphorylation induced by rotenone, and attenuated cell injury examined at 1, 2 and 8 h. Conclusions Our study suggested that ERK1/2 activation plays a detrimental role in rotenone toxicity, and raised the possibility that abnormal patterns of ERK1/2 activation may contribute to dopaminergic neuronal cell death in PD.