The Research Of The Effect And Mechanism Of Endoplasmic Reticulum Stress Induced By Homocysteine On The Model Of Dopaminergic Neurons

Part 1 The research of homocysteine-induced apoptosis through the pathway of endoplasmic reticulum stress on dopaminergic neuronsObjective: To study the apoptosis effect through the pathway of endoplasmic reticulum stress induced by homocysteine on dopaminergic neurons. Methods: Using PC12 cells differentiated by nerve growth factor as the model of dopaminergic neurons, the cells were treated by homocysteine on different concentrations(0, 0.1, 0.5, 1.0, 5.0 and 10mmol/L) for 24hours and different time points(0h, 6h, 12h, 24h and 48h)at the same concentration(5mmol/L). Cell viability was measured by MTT, flow cytometry was used to detect cell apoptosis ratio, and semi-quantitative RT-PCR analyzed the expression of Caspase-12.Results: After the PC12 cells were treated with Hcy, the cells viability declined in a time-dependent manner and the apoptosis ratio increased in a concentration-dependent manner. With the increase of apoptosis ratio and the decline of vitality, the expression of caspase-12 was corresponding enhanced.Conclusions: Homocysteine can induce apoptosis of dopaminergic neurons in vitro by the pathway of endoplasmic reticulum stress.Part 2 The research of the molecular mechanism of homocysteine-induced apoptosis on PC12 cellsObjective: To study the role of endoplasmic reticulum stress-related apoptosis pathway (IRE-1/TRAF-2 signal transduction pathway) in homocysteine-induced apoptosis on PC12 cells. Methods: Using PC12 cells differentiated by nerve growth factor as the model of dopaminergic neurons, the cells were treated by homocysteine on different concentrations(0, 0.1, 0.5, 1.0, 5.0 and 10mmol/L)for 24h and different time points(0h, 6h, 12h, 24h and 48h)at the same concentration(5mmol/L),then semi-quantitative RT-PCR analyzed the expression of TRAF-2 and IRE-1.Results: After the PC12 cells were treated with Hcy, the cells apoptosis was detected and with the increase of apoptosis ratio and the decline of vitality of PC12 cells, the expression of IRE-1 and TRAF-2 on PC12 cells was corresponding enhanced.Conclusions: Homocysteine can induce apoptosis of dopaminergic neurons in vitro by the pathway of endoplasmic reticulum stress. The activation of IRE-1/TRAF-2 signal transduction pathway is one of the mechanisms of above cells apoptosis.