Comparative Proteomic Analysis Of Hippocampal Proteins From Chronic Stressed Rats

Objective: To observe protein changes in hippocampus of rats after chronic stress and to find proteins correlated with stress-induced hippocampal injury. Methods: The animal model of chronic restraint stress was established by 3-weeks restraint in adult male wistar rats. After hippocampal proteins of restraint stress-treated and untreated rats were extracted, 2-DE was performed to separate them. The 2DE maps of chronic stress group and control group were analyzed to find differentially expressed proteins, and the differential proteins were identified by MALDI-TOF mass spectrometry and database index. Then the expression level of identified proteinsα-Synuclein and Dynamin 1 was further confirmed by western blot, meanwhile, the mRNA level of these two proteins was detected by real-time PCR. To explore the function of Dynamin1 in the progress of stress injury, the LTP was tested at differential restraint intensity rats, moreover, FM1-43 was used to investigate the change of synaptic vesicle endocytosis in the stress injury cell model. Results: 2-DE technique of hippocampal proteins with high reproducibility and resolution was established. After comparing hippocampal protein profiles between chronic stress group and control group, 14 protein spots were found altered and 11 of them were identified successfully by MALDI-TOF mass spectrometry. Among the 14 differential expressed proteins, 12 proteins were increased and 2 proteins were decreased after 3 weeks restraint stress. The expression ofα-Synuclein and Dynamin 1 were indeed decreased after 3 weeks restraint stress tested by western blot, and this result further confirmed the result of 2-DE.The result of real-time PCR indicated that the mRNA level ofα-Synuclein and Dynamin 1 was respectively decreased to 1/5 and 1/4 of the control group. The hippocampal LTP of different restraint intensity rats was gradually weakened while synaptic vesicle endocytosis was reduced in cell model, and both were accompanied by decreased expression of Dynamin1. Conclusions: Chronic stress changed the expression pattern of rat hippocampal proteins and 11 differental expressed proteins were identified by proteomic method.The decreased expression of Dynamin1 caused by stress might involve in the stress-induced damage of the LTP, learning and memory through inhibiting the synaptic vesicle recycling.