The Detection Of Plasma Free Amino Acids Of Major Depression Disorder

Background Major Depression Disorder is a common mental illness, as a syndrome it involves episodes of lost of interest, sadness, pessimism, slow thinking, negative beliefs about the self and somatic symptoms. the annual prevalence is 7% and the lifetime prevalence is 16%. The pathogenesis of depression is not well understood, recent evidence suggest that metabolic disorders of amino acids,which have been shown to interact with virtually every pathophysiologic domain to be involved in depression, including inflammatory cytokines, neurotransmitter metabolism, neuropeptide, neuroendocrine function, and neurol plasticity.Objective To identification and quantification of plasma free amino acids using amine reactive isotope coded tags (iTRAQ reagents) in conjunction with LC-MS/MS, investigate the possible role of difference amino acids and their metabolites in depressive episode.Methods Ten female subjects with first episode drug na?ve Major Depression Disorder (Meet the the Diagnostic and Statistical Manual of Mental Disorders IV) and Ten female normal subjects were recruited according to the inclusive and exclusive criteria. The diagnosis was made by experienced psychiatrists, the severity of the disease were evaluated by The Structured Clinical Interview for DSM-IV Axis I Disorders Research Version (SCID-Ⅰ) and Hamilton Depression Rating Scale-17. Blood was drawn from Median cubital vein, 5ml Samples were collected in K2EDTA-treated tubes. All blood samples were centrifuged at 1500×g for 10 minutes to pellet cellular elements within 30 minutes of sample collection. The supernatant plasma was then aliquoted and immediately frozen at ?80°C. Then detection the plasma free amino acids using amine reactive isotope coded tags (iTRAQ reagents) in conjunction with LC-MS/MS. Principal component analysis were Analyzed by MarkerView software, SPSS17.0 statistics package was used for statistical analysis of test results, P <0.05 denoted a statistically significant.Results Compared with contral group, the concentration of plasma free leucine, phenylalanine, tryptophan, methionine, tyrosine and Gamma-aminobutyric acid of MDD are lower than the control group(P<0.05), There is no difference of Basic and acidic amino acids between the two groups .Conclusions The lower concentration of plasma free leucine, phenylalanine, methionine, tryptophan, tyrosine and Gamma-aminobutyric acid may be associated with depression episode. The mechanism of depression episode may be a course of"Time dependent-- System imbalance", researchers must embrace the polysyndromic nature of depression,take the course of depression episode as a timeline and use a multidisciplinary approach to explore the neurobiological bases of Major Depression Disorder.