Distribution of Plasma One-Carbon Metabolism Factors and Amino Acids Profile in Depression State Treated with Paroxetine: A Model Study.

Stress may have an important role in the origin and progress of depression and can impair metabolic homeostasis. The one-carbon cycle (1-CC) metabolism and amino acid (AA) profile are some of the consequences related to stress. In this study, we investigated the Paroxetine treatment effect on the plasma metabolite alterations induced by forced swim stress-induced depression in mice. In this experimental study that was carried out in 2021, thirty male NMRI mice (6-8 weeks age, 30 ± 5 g) were divided into five groups: control, sham, paroxetine treatment only (7 mg/kg BW/day), depression induction, and Paroxetine+depression. Mice were subjected to a forced swim test (FST) to induce depression and then were treated with Paroxetine, for 35 consecutive days. The swimming and immobility times were recorded during the interventions. Then, animals were sacrificed, plasma was prepared and the concentration of 1-CC factors and twenty AAs was measured by spectrophotometry and high-performance liquid chromatography system (HPLC) techniques. Data were analyzed by SPSS, using One-Way ANOVA and Pearson Correlation, and P<0.05 was considered significant. Plasma concentrations of phenylalanine, glutamate, aspartate, arginine, ornithine, citrulline, threonine, histidine, and alanine were significantly reduced in the depression group in comparison with the control group. The Homocysteine (Hcy) plasma level was increased in the Paroxetine group which can be associated with hyperhomocysteinemia. Moreover, vitamin B12, phenylalanine, glutamate, ornithine, citrulline, and glycine plasma levels were significantly reduced in the depression group after Paroxetine treatment. This study has demonstrated an impairment in the plasma metabolites' homeostasis in depression and normal conditions after Paroxetine treatment, although, further studies are required.