Rotenone induces apoptosis of PC12 cells and alteration in mitochondrial membrane potential

Aim To investigate the toxicity of rotenone on rat PC12 cells and its potential mechanisms. Methods The cultivated rat PC12 cells were divided into control and rotenone-treated groups at various concentrations( 50,100,500,1 000,2 000 nmol·L- 1). The cell viability was assessed by MTT assay. Hoechst 33258 was employed to observe nucleus morphological changes and apoptotic rate. The expression of ɑ-synuclein protein was detected by immunocytochemistry. The mitochondrial membrane potential( MMP) was measured by JC-1 staining. Results As assayed by MTT,the cell viability with different concentrations of rotenone( 50,100,500,1 000,2 000 nmol · L- 1) was significantly decreased, reaching 83. 0%, 79. 5%,41. 0. 0%,26. 4% and 10. 2%,respectively,compared with the control group( P 0. 05). The pyknosis and fragmentation of nucleus were observed in rotenone exposure well by Hochest 33258 staining. The apoptotic rate was significantly increased in rotenonetreated cells by 6%,21%,64%,80% and 89%,respectively, as compared with control group( P 0. 05). The ɑ-synuclein accumulated evidently in rotenone treated groups,partially formed ɑ-synuclein-positive cytoplasmic inclusions,which were detected by immunocytochemistry technic. The MMP showed by red / green fluorescence ratio in rotenone- treated groups( 50,100,500,1 000,2 000 nmol·L- 1) was significantly reduced to 1. 21 ± 0. 13,0. 85 ± 0. 1, 0. 32 ± 0. 18,0. 25 ± 0. 09,and 0. 18 ± 0. 04,respectively,compared with 1. 92 ± 0. 15 of control cells as detected by JC-1 staining( P 0. 01). Conclusions Rotenone induces toxicity in PC12 cells by promoting apoptosis and ɑ-synuclein aggregation. It is suggested that decreased MMP levels might be involved in the mechanism.