title: Thymohexin exhibits cytoprotective effect in experimental gastric lesions in rats both through the inhibition of inducible nitric oxide synthase and reduction of oxidative mucosal damage.
abstract: OBJECTIVE
  Some short peptides have recently been reported to exhibit gastroprotective properties but the role of NO-synthase system in these mechanisms still leaves much to be elucidated. That is why the purpose of our study was to explore the gastroprotective effect of the hexapeptide Arg-α-Asp-Lys-Val-Tyr-Arg (thymohexin) under conditions of the modeling of iNOS activity.
  
  
  METHODS
  The studies were performed on 80 outbred male rats. Gastric lesions were induced with epinephrine (2 mg/kg) or indomethacin (30 mg/kg). Fifteen minutes before the exposure to ulcerogens rats were pretreated with thymohexin alone and combined with l-arginine or aminoguanidine. Twenty-four hours later gastric mucosa damage, L-arginine/NOS/NO system, processes of lipoperoxidation, superoxide dismutase and catalase activity were assessed.
  
  
  RESULTS
  Thymohexin markedly attenuated both epinephrine- and indomethacin-induced gastric ulceration in rats, decreasing the area and score of mucosal lesions (p<0.05), iNOS activity (p<0.05) and malonic dialdehyde content (p<0.05) in gastric mucosa. The cytoprotective effect of thymohexin was significantly enhanced by L-arginine and aminoguanidine. The combination of thymohexin and l-arginine was superior to that with aminoguanidine.
  
  
  CONCLUSIONS
  Thymohexin protects gastric mucosa against epinephrine- and indomethacin-induced gastric lesions in rats. Thymohexin-induced gastroprotection is probably mediated by inhibition of iNOS and decrease of the oxidative damage in gastric mucosa.
authors.affiliation: Department of Biochemistry of Danylo Halytsky Lviv National Medical University, Lviv, Ukraine. christinanasadyuk@gmail.com
authors.forename: C
authors.initials: C
authors.lastname: Nasadyuk
authors.forename: A
authors.initials: A
authors.lastname: Sklyarov
mesh_terms: D000818:Animals; D005753:Gastric Mucosa / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D008297:Male; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors*; D009842:Oligopeptides / Q000494:pharmacology*; D018384:Oxidative Stress; D051381:Rats; D013276:Stomach Ulcer / Q000201:enzymology / Q000378:metabolism / Q000517:prevention & control*
chemical_list: D009842:Oligopeptides; C080035:thymohexin; D052247:Nitric Oxide Synthase Type II