Effects of endoplasmic reticulum stress and its related apoptosis on selective death of dopaminergic neurons / 中华老年医学杂志

ABSTRACT

Objective To explore the effects of endoplasmic reticulum stress response(ERS) and its related apoptosis on dopaminergic neurons death.Methods NGF treated-PC12 cells were treated with 6-OHDA,MPP+ and rotenone.MTT assay and flow cytometry were used to measure the cell viability and the rate of cells apoptosis induced by those neurotoxins at different concentrations and times.The expressions of ERS-related gene XBP1,Grp78,CHOP,caspase-12 in drug-treated group and reserpine preincubation group were determined by RT-polymerase chain reaction(RT-PCR) and immunohistochemistry.Results After exposing to different concentration toxins,the vitality of PC12 cells was decreased by 52% at 100?mol/L 6-OHDA,by 44% at 75?mol/L MPP~+,and by 40% at 20 nmol/L rotenone for 24 hours respectively and ws decreased in a dose dependent manner. FCM assay confirmed time-dependent cell apoptosis.The apoptotic cells ratio of 24 h groups were (31.22?3.21)%,(27.46?2.35)%,(29.26?2.53)%,respectively(P＜0.01).In 6-OHDA groups,the gene expressions of XBP1,Grp78 were approximately 2-fold increased after 8 h exposure, CHOP reached peak level at 16 h(149.5?3.3% vs 35.9?1.8%,P＜0.01).The transcription level of caspase-12 was significantly higher than normal control at 16h[(95.4?2.8% vs(23.8?3.0)%, P＜0.01],but was alleviated by reserpine prcincubation(62.15?4.3%,P＜0.05).The increased expressions of Grp78 and CHOP after drug exposure were confirmed by immunochemistry stain.The similar results were observed in MPP~+ and rotenone groups.Conclusions The excessive ERS and ERS-activated cell apoptosis pathway may be involved in selective death of dopaminergic neurons.