STUDY OF THE EFFECTS OF METYLENE BLUE ON INJURY ISCHEMIA REPERFUSION IN A LIVER FIBROSIS MODEL SECONDARY MIXED LIGATORY OF THE BILE DUCT.

• Grant number: 24/05750-2
• Support Opportunities: Regular Research Grants
• Start date: November 01, 2024
• End date: October 31, 2026
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Estela Regina Ramos Figueira
• Grantee: Estela Regina Ramos Figueira
• Host Institution: Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Associated researchers: Flávio Henrique Ferreira Galvão ; Joel Avancini Rocha Filho ; Luiz Augusto Carneiro D'Albuquerque ; Márcia Saldanha Kubrusly

Abstract

Introduction: Hepatic ischemia reperfusion injury (IR) is still a complication with high morbidity in liver transplantation, liver resection surgeries and hypovolemic shock. Despite the vast literature on hepatic IR, there is a lack of information on ischemia reperfusion injury (IR) in the liver with fibrosis. On the other hand, there are publications related to liver resections in patients with cirrhosis, which may be associated with a higher incidence of complications such as bleeding and postoperative liver failure. Then studies on the pathophysiology of IR injury in liver fibrosis are necessary.Aim: 1) To evaluate mixed bile duct ligation and time to develop fibrosis;2) to evaluate the effects of IR injury in animals with liver fibrosis caused by mixed bile duct ligation; 3) to evaluate the effects of methylene blue administration on ischemia-reperfusion injury of the liver with fibrosis.Methods: A group of rats will undergo mixed bile duct ligation and compared to the classic group to evaluate the development of fibrosis at 2, 4, 6, 12 and 24 weeks. After that, animals with fibrosis will be divided into 5 groups of 10 animals. Sham group; control group where animals with fibrosis will be subjected to 60 minutes of ischemia and 4 hours of reperfusion; methylene blue group 1, animals with fibrosis subjected to IR, treated with 20 mg/kg of methylene blue, 5 min before ischemia; methylene blue group 2, animals subjected to IR, treated with methylene blue 5 min before reperfusion. Clinical monitoring of the evolution of animals with fibrosis will be carried out. The hemodynamic conditions of animals will be evaluated, with collection of mean arterial pressure and portal vein flow. At the end of the experiments, blood and tissues such as liver will be collected. Hemodynamic parameters, mean arterial pressure and portal flow, biochemical tests AST, ALT, alkaline phosphatase, GGT, bilirubin, albumin, blood count and creatinine, prothrombin time and interleukins will be evaluated. The liver tissue will be sent for histopathological analysis, analysis of JNK, HIF-1(Hypoxia Inducible Factor 1 Alpha), B-catenin, HMGB-1(High Mobility Group Protein B1) and NFkB, analysis of oxidation stress, analysis of mitochondrial functions and analysis of the Nrf2, KEAP-1, ATF3, ATF4, ACTB genes. (AU)