Lyso-07, an indol-thiazolidine PPARγ agonist, protects ulcer gastric induction by modulating of neutrophil mobilization and NOS protein expression

JR Santin1, ID Machado1, SFP Rodrigues1, V Ferraz de Paula1, S Teixeira2, MN Muscará2, SL Galdino3, IR Pitta3, SHP Farsky1. 1University of São Paulo, Clinical and Toxicological Analyses, 05508-900, Brazil, 2University of São Paulo, Pharmacology, 05508-900, Brazil, 3Federal University of Pernambuco, Planning and Synthesis of Drugs, 50670-901, Brazil

Introduction: Gastric ulcer is characterized by intense neutrophil migration and gastric tissue necrosis. Recently, it has been proposed that indol-thiazolidine molecule may act as anti-ulcer agents. This study evaluated the effects of an indol-thiazolidine molecule named Lyso-07 in ethanol/HCl-induced ulcer model.

Methods: Swiss male mice (25-35 g) were treated with carboxymethyl cellulose (vehicle), Lyso-07 or Pioglitazone (p.o), 1 hour before oral administration of ethanol/HCl solution (60%/0.03M). Pharmacological treatments were also carried out before vehicle, Lyso-07 or pioglitazone to investigate the PPARγ agonist activity of Lyso-07, (GW9962, a peroxisome-proliferate activated receptorγ (PPARγ) antagonist; 2 mg/kg, i.p.); the participation of neutrophils (anti-granulocyte antibody; 50μL, i.p.) and nitric oxide (NO; L-NAME, 70 mg/kg, i.p.). One hour after gastric damage induction, blood and bone marrow perfusate were collected to quantify number of neutrophils; gastric tissue was employed to quantify percentage of lesion area, myeloperoxidase activity (MPO), morphological analysis, inducible and endothelial nitric oxide synthase (iNOS and eNOS) expression and to study the microcirculatory network by intravital microscopy.

Results: Data obtained showed extensive damage in the gastric tissue 1 hour after ethanol/HCl administration and that Lyso-07 pre-treatment prevented, dose-dependent, the lesion formation (p<0.01). Equivalent gastroprotective protection was induced by 25 mg/kg of Lyso-07 and 40 mg/Kg of pioglitazone. These effects were PPARγ agonist activity dependent, because Lyso-07 and pioglitazone protective effect was reversed in mice pre-treated with GW9962 (p<0.01). Neutrophil is a hallmark of the lesion, evidenced by enhanced MPO (21.01±1.58) activity and number of leukocytes in the damage gastric tissue in the vehicle group, which were reduced by Lyso-07 (6.10±0.56) or pioglitazone (8.44±2.47) treatments. In addition, the gastric lesion was lesser in anti-granulocyte antibody treated mice (p<0.05). Lyso-07 or pioglitazone treatments reduced the number of circulating neutrophils and enhanced mature granulocyte in the bone marrow. Ethanol/HCl administration caused stasis in the microcirculatory network, and pioglitazone or Lyso-07 pre-treatments reversed the vessel stasis. NO has been proposed as protective endogenous mediator on gastric damage. Data obtained showed that the pre-treatment with L-NAME inhibited the protective effect of Lyso-07 on ethanol/HCl-damage on microcirculatory blood flow, and the possible participation on NO on protective effect of Lyso-07 was evidenced by reduced and elevated iNOS and eNOS expression in the damage gastric tissue of Lyso-07 treated animals. Pioglitazone treatment did not alter the eNOS protein expression.

Conclusion: Data obtained show that Lyso-07 exerts PPARγ agonist activity and its gastroprotective actions in the ethanol/HCl-induced gastric tissue damage involve the inhibition on neutrophil migration and reversion of microcirculatory vessels stasis. The latter effect seems to be dependent on the action of Lyso-07 on NO production, especially by enhancing and decreasing eNOS and iNOS expression, respectively.

Sources of research support: FAPESP (2010/17175-0; 2011/01848-8).