Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Nov 21, 2015; 21(43): 12351-12360
Published online Nov 21, 2015. doi: 10.3748/wjg.v21.i43.12351
N-acetylcysteine modulates angiogenesis and vasodilation in stomach such as DNA damage in blood of portal hypertensive rats
Francielli Licks, Renata Minuzzo Hartmann, Camila Marques, Elizângela Schemitt, Josieli Raskopf Colares, Mariana do Couto Soares, Juliana Reys, Camila Fisher, Juliana da Silva, Norma Possa Marroni
Francielli Licks, Renata Minuzzo Hartmann, Elizângela Schemitt, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 90040-060, Brazil
Camila Marques, Instituto de Tecnologia do Paraná, Curitiba 90040-060, Brazil
Josieli Raskopf Colares, Mariana do Couto Soares, Juliana Reys, Camila Fisher, Juliana da Silva, Norma Possa Marroni, Universidade Luterana do Brasil, Canoas 92425-900, Brazil
Author contributions: Licks F, Hartmann RM, Marques C, Schemitt E, Colares JR, Soares MC, Reys J and Fisher C contributed equally to this work; Marroni NP designed the research; Licks F, Hartmann RM, Schemitt E, Colares JR and Soares MC performed the research; Reys J, da Silva J contributed new reagents/analytic tools; Licks F and Hartmann RM analyzed the data; and Licks F wrote the paper.
Supported by Brazilian agencies Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fundo de Incentivo à Pesquisa e Eventos - Hospital de Clínicas of Porto Alegre (FIPE project nº 11-0293); the Laboratory of Experimental Hepatology and Gastroenterology (HCPA/UFRGS), Universidade Federal do Rio Grande do Sul; and the Oxidative Stress and Antioxidants Laboratory, Universidade Luterana do Brasil.
Institutional review board statement: The study was reviewed and approved by the Hospital de Clínicas de Porto Alegre and Universidade Luterana do Brasil’s Institutional Review Board.
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee of the Hospital de Clínicas de Porto Alegre (11-0293).
Conflict-of-interest statement: The authors of the present study declare no conflict-of-interest.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at Participants gave informed consent for data sharing. No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Francielli Licks, MSc, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 90040-060, Brazil.
Telephone: +55-51-33598937
Received: March 25, 2015
Peer-review started: March 27, 2015
First decision: April 24, 2015
Revised: May 14, 2015
Accepted: July 18, 2015
Article in press: July 18, 2015
Published online: November 21, 2015

AIM: To evaluate the antioxidant effect of N-acetylcysteine (NAC) on the stomach of rats with portal hypertension.

METHODS: Twenty-four male Wistar rats weighing ± 250 g were divided into four experimental groups (n = 6 each): Sham-operated (SO), SO + NAC, partial portal vein ligation (PPVL), and PPVL + NAC. Treatment with NAC in a dose of 10 mg/kg (i.p.) diluted in 0.6 mL of saline solution was administered daily for 7 d starting 8 d after the surgery. Animals from the PPVL and SO group received saline solution (0.6 mL) for the same period of time as the PPVL + NAC and SO + NAC group. On the 15th day the animals were anesthetized and we evaluated portal pressure by cannulating mesenteric artery. After, we removed the stomach for further analysis. We performed immunohistochemical analysis for endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF), and nitrotirosine (NTT) proteins in stomach. We also evaluated eNOS and VEGF by Western blot analysis and assessed DNA damage in blood samples by the comet assay.

RESULTS: The portal hypertension group exhibited increases in portal pressure when compared to SO group (29.8 ± 1.8 vs 12.0 ± 0.3 mmHg) (P < 0.001). The same was observed when we compared the eNOS (56.8 ± 3.7 vs 13.46 ± 2.8 pixels) (P < 0.001), VEGF (34.9 ± 4.7 vs 17.46 ± 2.6 pixels) (P < 0.05), and NTT (39.01 ± 4.0 vs 12.77 ± 2.3 pixels) (P < 0.05) expression by immunohistochemistry of the PPVL animals with the SO group. The expression of eNOS (0.39 ± 0.03 vs 0.25 ± 0.03 a.μ) (P < 0.01) and VEGF (0.38 ± 0.04 vs 0.26 ± 0.04 a.μ) (P < 0.01) were also evaluated by Western blot analysis, and we observed an increase of both proteins on PPVL animals. We also evaluated the DNA damage by comet assay, and observed an increase on damage index and damage frequency on those animals. NAC decreased portal pressure values in PPVL + NAC animals (16.46 ± 2 vs 29.8 ± 1.8 mmHg) (P < 0.001) when compared to PPVL. The expression of eNOS (14.60 ± 4.1 vs 56.8 ± 3.7 pixels) (P < 0.001), VEGF (19.53 ± 3.2 vs 34.9 ± 4.7 pixels) (P < 0.05) and NTT (21.84 ± 0.7 vs 39.01 ± 4.0 pixels) (P < 0.05) evaluated by immunohistochemistry were also reduced in PPVL + NAC animals. Also, when evaluated by Western blot eNOS expression (0.32 ± 0.03 vs 0.39 ± 0.03 a.μ) (P < 0.05) and VEGF expression (0.31 ± 0.09 vs 0.38 ± 0.04 a.μ) (P < 0.01). Furthermore, NAC modulated DNA damage in PPVL + NAC animals.

CONCLUSION: In view of these results, we believe NAC is able to protect the stomach from the alterations induced by the PPVL procedure.

Keywords: N-Acetylcysteine, Portal hypertension, Gastropathy, Oxidative stress, Antioxidant

Core tip: Portal hypertension (PH) is a syndrome with serious manifestations as ascites, hepatic encephalopathy and development of collateral circulation, characterized by vasodilation and angiogenesis. This mechanism, intended to divert blood from the site of obstruction, is the leading cause of death among these patients, since it leads to upper gastrointestinal bleeding. Therapies that may contribute to control the development of collateral circulation are been investigated in an attempt to improve the quality of life of PH patients. This paper proposes a novel therapy, using an antioxidant effective in reducing this collateral circulation in an animal model of portal hypertension.