title: Hyperhomocysteinemia is a result, rather than a cause, of depression under chronic stress.
abstract: BACKGROUND
  Although the accumulation of homocysteine (Hcy) has been implicated in the pathogenesis of depression, whether Hcy is directly involved and acts as the primary cause of depressive symptoms remains unclear. The present study was designed to clarify whether increased Hcy plays an important role in stress-induced depression.
  
  
  RESULTS
  We employed the chronic unpredictable mild stress model (CUMS) of depression for 8 weeks to observe changes in the plasma Hcy level in the development of depression. The results showed that Wistar rats exposed to a series of mild, unpredictable stressors for 4 weeks displayed depression-like symptoms such as anhedonia (decreased sucrose preferences) and a decreased 5-Hydroxy Tryptophan (5-HT) concentration in the hippocampus. At the end of 8 weeks, the plasma Hcy level increased in the CUMS rats. The anti-depressant sertraline could decrease the plasma Hcy level and improve the depression-like symptoms in the CUMS rats. RhBHMT, an Hcy metabolic enzyme, could decrease the plasma Hcy level significantly, although it could not improve the depressive symptoms in the CUMS rats.
  
  
  CONCLUSIONS
  The results obtained from the experiments did not support the hypothesis that the increased Hcy concentration mediated the provocation of depression in CUMS rats, and the findings suggested that the increased Hcy concentration in the plasma might be the result of stress-induced depression.
authors.affiliation: Tianjin Centers for Disease Control and Prevention, Tianjin, China.
authors.forename: Shen
authors.initials: S
authors.lastname: Chengfeng
authors.affiliation: Institute of Health & Environmental Medicine, Tianjin, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Wei
authors.affiliation: Beijing Institute of Basic Medical Sciences, Beijing, China; Institute of Health & Environmental Medicine, Tianjin, China.
authors.forename: Wang
authors.initials: W
authors.lastname: Xinxing
authors.affiliation: Institute of Health & Environmental Medicine, Tianjin, China.
authors.forename: Wu
authors.initials: W
authors.lastname: Lei
authors.affiliation: Beijing Institute of Basic Medical Sciences, Beijing, China.
authors.forename: Zhan
authors.initials: Z
authors.lastname: Rui
authors.affiliation: Beijing Institute of Basic Medical Sciences, Beijing, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Lingjia
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D050940:Betaine-Homocysteine S-Methyltransferase / Q000627:therapeutic use; D002908:Chronic Disease; D003863:Depression / Q000097:blood / Q000150:complications* / Q000188:drug therapy; D004195:Disease Models, Animal; D006710:Homocysteine / Q000097:blood; D020138:Hyperhomocysteinemia / Q000097:blood / Q000188:drug therapy / Q000209:etiology*; D008297:Male; D008715:Methionine / Q000627:therapeutic use; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000627:therapeutic use; D020280:Sertraline / Q000494:pharmacology / Q000627:therapeutic use; D013315:Stress, Psychological / Q000097:blood / Q000150:complications* / Q000188:drug therapy
chemical_list: D011994:Recombinant Proteins; D006710:Homocysteine; D008715:Methionine; C494548:BHMT protein, human; D050940:Betaine-Homocysteine S-Methyltransferase; D020280:Sertraline