Extracellular Signal-regulated Kinase Regulates Rotenone-induced Injury In Pc12 Cells

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 pheochromocytoma(PC12)cells treated with rotenone were used as the cell model of Parkinson disease (PD). Cell viability of PC12 cells after exposure to rotenone was detected by MTT (methyl thiazolyl tetrazolium) method. Immunohistochemistry was used to detect the phosphorylation of ERK1/2 within 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 5μmol/L rotenone) declined with the increase of exposure time from 1 h to 24 h (compared with control groups, P<0.05). After exposed to rotenone, phosphorylated ERK1/2 aggregated in the PC12 cells; Western blotting indicated that rotenone induced a biphasic phosphorylation of ERK1/2, which arised 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 inhibited ERK1/2 phosphorylation induced by rotenone, and attenuated cell injury at 1 h, 2 h and 8 h (P<0.05).Conclusion Our results suggest that ERK1/2 activation plays a detrimental role in rotenone toxicity, and raise the possibility that abnormal patterns of ERK1/2 activation may contribute to dopaminergic neuronal cell death in PD.