title: Melatonin reduces colon immunological injury in rats by regulating activity of macrophages.
abstract: OBJECTIVE
  To investigate the effects of melatonin on the colon immunological injury of rats and the role of macrophages in this process.
  
  
  METHODS
  The rats colitis was established by intrarectal injection with 2,4,6-trinitrobenzenesulfonic acid (TNBS) and ethanol. The animals were randomized into 6 groups: normal group, model group, 5-aminosalicylic acid group (100 mg/kg), and melatonin group (2.5, 5.0, and 10.0 mg/kg), treated intrarectally with saline, saline, 5-aminosalicylic acid, and melatonin, respectively (once a day, from d 7 after colitis established to d 28). At the end of the experiment, the colon mucosa damage index (CMDI), the score of histology (HS), the level of myeloperoxidase(MPO), and the sore of occult blood test (OBT) were evaluated. Meanwhile, the activity of interleukin-1 (IL-1), tumour necrosis factor-alpha (TNF-alpha, and nitric oxide (NO) were also detected.
  
  
  RESULTS
  After treated with TNBS and ethanol, the extents of CMDI, HS, OBT, and the level of MPO in model group were more higher than that in normal group. Melatonin could alleviate the colon injury, and reduce the level of MPO and the degree of OBT. The activity of IL-1, TNF-alpha, and NO which released mainly from macrophages was elevated remarkably. Melatonin could depress all this parameters.
  
  
  CONCLUSIONS
  Melatonin could reduce the colon damage in the colitis rats by regulating macrophage activity.
authors.affiliation: Renmin Hospital of Wuhan University, Wuhan 430060, China. meiqiao@hotmail.com
authors.forename: Qiao
authors.initials: Q
authors.lastname: Mei
authors.forename: Jie-Ping
authors.initials: JP
authors.lastname: Yu
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.forename: Li
authors.initials: L
authors.lastname: Xiang
authors.forename: Li
authors.initials: L
authors.lastname: Yue
mesh_terms: D000818:Animals; D003092:Colitis / Q000139:chemically induced / Q000276:immunology / Q000517:prevention & control*; D003106:Colon / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D000431:Ethanol; D007375:Interleukin-1 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000473:pathology; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology; D008297:Male; D008550:Melatonin / Q000494:pharmacology / Q000627:therapeutic use*; D009569:Nitric Oxide / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D014302:Trinitrobenzenesulfonic Acid; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D007375:Interleukin-1; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D000431:Ethanol; D014302:Trinitrobenzenesulfonic Acid; D008550:Melatonin