Serum Proteomic Analysis Of Depressive Rats Of Spontaneous Withdrawal After Morphine Dependence

Opiate withdrawal in human addicts can result in not only a number of well-characterized autonomic and somatic symptoms, but also emotional or affective symptoms such as depressed mood/dysphoria, restlessness, hyperirritability, and anxiety. These negative emotional states resulting from withdrawal may contribute to escalation, compulsive use, maintenance of use, and relapse after periods of abstinence. In this study, we successfully screened depressive-like model of rats after morphine withdrawal, and then utilized serum comparative proteomic analysis and MADLA-TOF to find differentially expressed proteins and their information, and this may be helpful to discover the pathophysiologic molecular mechanisms involved in depressive-like symptom after withdrawal and to guide better treatment of depressive-like symptom after withdrawal.At first,30 rats with basic open-filed test result alike were chosen and randomly divided into morphine treatment group and saline treatment group. Morphine group was administrated by intraperitoneally administrated (IP) for 7 days to establish morphine dependence rat model, then screened rats of depressive-like symptom after spontaneous withdrawal. We observed their behavior on the third and ninth day after withdrawal in following tests:the open field test, the sucrose preference test, the forced swimming test (FST), and found that rats withdrawal from morphine dependence had somatic withdrawal symptom and depressive-like behavior:on withdrawal d3, the travel distances and the scores of rearing decreased (P<0.05), there was significant differences between the normal group and the withdrawal group, percentage of sucrose consumption decreased (P<0.05), but the immobility time of two groups had little differences; On withdrawal d9, not only the travel distances and scores of rearing decreased, but also the time prolonged in the FST, but no differences in the open field test or in the sucrose preference test or in FST was observed. Rats still less active on withdrawal d9 were thought as depressive-like rats, and then we extracted serum from the control rats and the depressive rats respectively and separated and identified differentially expressed proteins spots in serum at different time at different group with the techniques of two-dimensional electrophoresis (2-DE) and mass spectrometer (MS). Through image analysis of serum proteins, we could obtain about 420 spots by coomassie staining. Twenty-five protein spots of interest were excised from the gels and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Twenty-two protein spots were identified in the database. These protein spots could be divided into five kinds:the first was about receptor proteins; the second was about acute phase proteins; the third was about lipoproteins; the fourth was about serum protease; the fifth was associated with proteins that were not identified. These differentially expressed proteins can offer us a clue about the biomarkers of the depressive-like symptom of morphine withdrawal.