Effects Of Chronic Unpredictable Stress On The Levels Of CAMP Response Element Binding Protein In The Rat Hippocampus

IntroductionDepression is the most popular kind of psychical disease. It has a higher recurrent rate and lifetime morbidity. There is growing evidence that pathophysiology of depression is associated with impairments of neu-ronal plasticity and cellular resilience. The damage of hippocampal neuron is the key part in plasticity regulation of synapse and play a critical role in the mechanism of depression. Chronic stress can cause damage to brain, especially to the structure and the function of hippocampus, ultimately leads to the onset of depression. The cAMP responsive element binding protein (CREB) is a nuclear transcription factor that modulates several signaling pathways concerned with neuronal plasticity, is a key part of many regulations including neuronal plasticity and cell resilience. This study observes the effects of chronic unpredictable stress on the levels of CREB expression, to discuss the mechanisms of brain damage and neuron protection in depression causing by chronic stress.Materials1. Animals: Forty-eight male wistar rats.2. Reagents: Rabbit anti CREB antibody (Cell Signaling Technology);Goat anti rabbit SABC Kits(Beijing Zhongshan Co. );DAB Kits(Bei-jing Zhongshan Co. ).3. Apparatus: YSD-4 electronic stimulus instrument, Meta Mor-ph/Cool Snap_fx/Ax70 computer image analysis system.Methods1. According to Open—field, forty—eight rats were randomly divided into the experimental group KEG1, 12rats), the experimental group 2 (EG2, 12rats) , and the control group 1(CG1, 12rats) , the control group 2(CG2, 12rats).2. The experimental group rats randomly accepted different stimulus for 21 days to get depressive model rats, and all rats were taken Open-field test again on the 22ed day.3. The CREB in different regions of rat hippocampus were detected by immunohistochemistry and western blotting of special antibody.ResultsThe weight and the numbers of field segments entered of experimental group were obviously lower then the control group.Compared to control group, the expression of CREB in depression rats in hippocampus CA3 region and dentate gyrus was significantly de-creased(P<0. 05).Conclusion1. Chronic composite stresses cause rats losing weight and decrease the research and modify behaviors.2. Compared to control group, the expression of CREB in chronic stress rats in hippocampus CA3 region and dentate gyrus was significantly decreased.3. CREB is possible involved in the pathophysiology of depression including the alterations of neuroplasticity. The factors or methods that can promote the expression of CREB may improve neuron survival and recov-er ability, which develops a new way for the etiopathogenisis and the clinical therapy of depression.