Primary research on abnormal hippocampal synaptic transmission induced in a chronic mild stressed rat model

Abstract

Objective The differential proteins of hippocampal synapses in depression model rat was analyzed by two-dimensional gel electrophoresis.To provide clues for studies on the synaptic pathogenesis of depression. Methods According to the baseline of sucrose consumption, 58 male Sprague-Dawley rats were divided into Chronic Mild Stress (CMS) and control groups randomly (n=29 per group). After establishment of rat depression model via CMS experimental mode, rat hippocampal synapses from the CMS and control groups were prepared by discontinuous sucrose density gradient centrifugation.Subsequently, the differential proteomics analysis were performed by conventional two-dimensional gel electrophoresis (2DE) and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF-MS). Results The results from the sucrose consumption test showed consistent decreases of sucrose intake and preference in the CMS group (P<0.05), suggesting that the depression model rat had been successfully established. Furthermore, by 2DE combined with mass spectrometry analysis (2DE-MS), 16 differentially expressed proteins were obtained, of which 12 were up-regulated and 4 were down-regulated in the chronic mild stressed group as compared with the control group. These proteins were mainly classified into four functional categories including energy metabolism, substance metabolism, cytoskeleton and vesicular transport. Conclusion Differential proteins found in this study may participate in an important mechanism that underlies the abnormal transmission of hippocampal synapses found in the chronic mild stressed rat, thereby providing valuable clues for studies on the pathogenesis of depression. Key words: Depressive disorder; Chronic mild hippocampus; Hippocampus; Synapses; Two-dimensional gel electrophoresis; Proteomics