Evaluation of the inhibitory effect of n-acetylcysteine on irinotecan-induced esteatohepatite model in mice
| Autor: | Renato Mazon Lima Verde Leal |
|---|---|
| Jazyk: | portugalština |
| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Biblioteca Digital de Teses e Dissertações da UFCUniversidade Federal do CearáUFC. |
| Druh dokumentu: | masterThesis |
| Popis: | Background: Colorectal cancer (CRC) is currently one of the most common cancers worldwide. The liver is the main site of metastasis in advanced CRC. Regimens based on irinotecan (IRI) have been used for the treatment of metastatic CRC, usually resulting in the conversion of unresectable liver metastases into resectable metastases. However, these regimens are associated with the occurrence of non-alcoholic steatohepatitis (NASH), which often limits the treatment. The pathogenesis of NASH caused by IRI remains unclear. Recently, our group developed a novel IRI-induced mouse NASH model. N-acetylcysteine (NAC) is an acetylated derivative of L-cysteine that carries a thiol (-SH) group that reacts and neutralizes free radicals, as well as restores cellular antioxidants such as glutathione. NAC is used in clinical practice for the treatment of liver damage induced by paracetamol. Objectives: To assess the protective effect of NAC on IRI-induced ASH. Methods: Male Swiss mice (25 g, n = 8) received saline (5 mL/kg, i.p), NAC (1,000 mg/kg, s.c), IRI (50 mg/kg, i.p), or NAC (10, 100, or 1000 mg/kg) + IRI 3 Ã/week for 7 weeks. Weight variation and survival were assessed. At the end of the treatment, blood was collected for the determination of serum levels of ALT and AST (U/L), and the animals were sacrificed for liver collection and weighing (mg/30 g of animal). Histopathological analysis was performed according to Kleinerâs criteria for NASH (lobular inflammation [0â3], steatosis [0â3], and vacuolization [0â3]), as well as measurement of IL-1β production (pg/mL) and immunohistochemical analysis (IHC) of IL-1β, iNOS and nitrotyrosine. For statistical analysis, ANOVA/studentâs Newman Keul test or the Kruskal Wallis/Dunn test was used. The level of significance was set at P < 0.05. (CEPA 1/12). Results: IRI induced a significant (P < 0.05) reduction in survival (44%), a marked increase in the serum concentrations of ALT (48.99  13.4), AST (90.55  19.7), cytokine IL1-β (288.5  35.86), liver weight (1,814  159.3), and an increase in Kleiner scores [5.5 (4â7)] vs. the saline group (survival: 100%; ALT: 17.31  5.2; AST: 44.58  5.4; cytokine IL1-β (104  36.9); liver weight: 1,425  39.5; Kleiner: 0 (0â0). These changes were prevented (P < 0.05) by treatment with NAC. NAC increased the survival of animals injected with IRI (10 mg/kg: 90%; 100 mg/kg: 80%). NAC 10 mg/kg prevented the increase of the enzymes ALT: 26.95  7 and AST: 56.42  4.8; NAC (10 mg/kg and 1,000 mg/kg) inhibited the increase in the levels of cytokine IL-1 (152  23.92 and 149  17.21, respectively); NAC (10 mg/kg and 100 9 mg/kg) reversed the increase in liver weight (1,375  68.2 and 1,467  28.6, respectively), and NAC 10 mg/kg reversed the increase in Kleiner scores: 2 [1â4]) vs. the IRI group. The IHC of the IRI group showed a significant increase in immunostaining for IL-1 (3[1â3]), iNOS (3[3â3]) compared to the saline group (IL-1: 0[0â1]; iNOS: 1[1â2]); and NAC at a dose of 10 mg/kg prevented the increase in immunostaining (IL-1: 1[1â1]; iNOS: 2[1â2]) vs. the IRI group. Conclusion: NAC at a dose of 10 mg/kg prevented changes in the clinical, histopathological, biochemical, and inflammatory parameters of the IRI-induced NASH model. Current studies are focused on identifying the mechanisms involved in this protective effect. IntroduÃÃo: O cÃncer colorretal (CCR) à um dos mais comuns tumores malignos atualmente. Na evoluÃÃo natural da doenÃa, o fÃgado à o principal sÃtio de metÃstases. Regimes à base de irinotecano (IRI) tÃm sido utilizados no tratamento do CCR metastÃtico, permitindo muitas vezes a conversÃo de metÃstases hepÃticas irressecÃveis em ressecÃveis. Contudo, tais regimes estÃo associados ao surgimento de esteatohepatite nÃo alcoÃlica (NASH), muitas vezes limitante do tratamento. A patogÃnese da NASH por IRI ainda à desconhecida. Recentemente, nosso grupo desenvolveu um modelo inÃdito de NASH induzida por IRI. N-acetilcisteÃna (NAC) à um derivado acetilado da L-cisteÃna que apresenta na sua estrutura quÃmica o grupo sulfidrila(-SH), o qual pode reagir e neutralizar radicais livres, alÃm de restabelecer os protetores celulares do estresse oxidativo, como a glutationa. NAC à utilizada na prÃtica clÃnica para o tratamento da lesÃo hepÃtica induzida por acetaminofen. Objetivos: Avaliar o efeito protetor da NAC sobre a NASH induzida por IRI. MÃtodos: Camundongos Swiss machos (25g, n=8) receberam salina (5 mL/Kg, i.p), NAC (1000 mg/Kg, s.c), IRI (50 mg/Kg, i.p) ou NAC (10, 100 ou 1000mg/Kg)+IRI 3x/semana/7semanas. Avaliou-se a variaÃÃo ponderal e a sobrevida. Ao final do tratamento, o sangue foi coletado para dosagem sÃrica de ALT e AST (U/L) e realizou-se o sacrifÃcio dos animais para coleta do fÃgado e pesagem (mg/30g de animal), anÃlise histopatolÃgica de acordo com os CritÃrios de Kleiner para NASH (inflamaÃÃo lobular[0-3],esteatose[0-3] e vacuolizaÃÃo[0-3]), mensuraÃÃo da atividade da citocina Interleucina-1 (IL-1β, pg/mL), e ensaio imunoistoquÃmico (IMQ) para IL-1β, Ãxido NÃtrico Sintase induzida (iNOS) e nitrotirosina. Na anÃlise estatÃstica utilizou-se ANOVA/Student Newman Keul ou Kruskal Wallis/Dunn. Um nÃvel de significÃncia menor que 5% foi aceito (p |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|