title: L-arginine and glycine supplementation in the repair of the irradiated colonic wall of rats.
abstract: OBJECTIVE
  Radiotherapy is widely used for cancer treatment but has harmful effects. This study aimed to assess the effects of L-arginine and glycine supplementation on the colon wall of rats submitted to abdominal irradiation.
  
  
  METHODS
  Forty male Wistar rats were randomly divided into four groups: I-healthy, II-irradiated with no amino acid supplementation, III-irradiated and supplemented with L-arginine, and IV-irradiated and supplemented with glycine. The animals received supplementation for 14 days, with irradiation being applied on the eighth day of the experiment. All animals underwent laparotomy on the 15th day for resection of a colonic segment for stereologic analysis. Parametric and nonparametric tests were used for statistical analysis, with the level of significance set at p ≤0.05.
  
  
  RESULTS
  Stereologic analysis showed that irradiation induced a reduction of the total volume of the colon wall of group II and III animals compared to healthy controls, but not of group IV animals supplemented with glycine. The mucosal layer of the irradiated animals of all groups was reduced compared to healthy group I animals, but supplementation with L-arginine and glycine was effective in maintaining the epithelial surface of the mucosal layer.
  
  
  CONCLUSIONS
  The present results suggest that glycine supplementation had a superior effect on the irradiated colon wall compared to L-arginine supplementation since it was able to maintain the thickness of the wall and the epithelial surface of the mucosa, whereas L-arginine maintained the partial volume of the epithelium and the epithelial surface, but not the total volume of the intestinal wall.
authors.affiliation: Laboratory of Experimental Surgery, Rio de Janeiro State University, Rio de Janeiro, Brazil.
authors.forename: Etiene
authors.initials: E
authors.lastname: de Aguiar Picanço
authors.forename: Francisco
authors.initials: F
authors.lastname: Lopes-Paulo
authors.forename: Ruy G
authors.initials: RG
authors.lastname: Marques
authors.forename: Cristina F
authors.initials: CF
authors.lastname: Diestel
authors.forename: Carlos Eduardo R
authors.initials: CE
authors.lastname: Caetano
authors.forename: Mônica Vieira Mano
authors.initials: MV
authors.lastname: de Souza
authors.forename: Gabriela Mendes
authors.initials: GM
authors.lastname: Moscoso
authors.forename: Helena Maria F
authors.initials: HM
authors.lastname: Pazos
mesh_terms: D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D001835:Body Weight / Q000187:drug effects; D019587:Dietary Supplements; D005247:Feeding Behavior / Q000187:drug effects; D005998:Glycine / Q000008:administration & dosage / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000473:pathology*; D008297:Male; D009929:Organ Size / Q000187:drug effects; D011827:Radiation; D051381:Rats; D017208:Rats, Wistar; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D001120:Arginine; D005998:Glycine