Evaluation of the healing effect of low-intensity laser on the development of liver fibrosis induced by the bile duct ligation model

• Grant number: 24/18437-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2025
• End date: February 28, 2026
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Márcia Regina Nagaoka
• Grantee: Luiz Guilherme Reis dos Santos
• Host Institution: Instituto de Saúde e Sociedade (ISS). Universidade Federal de São Paulo (UNIFESP). Campus Baixada Santista. Santos , SP, Brazil

Abstract

Low-level laser therapy (LLLT) is recognized for its anti-inflammatory and wound-healing properties, although its effect on the liver remains poorly understood. Preliminary results suggest a potential healing effect of LLLT for 7 days on hepatic fibrogenesis induced by an experimental bile duct ligation (BDL) model.Objective: To investigate the healing effect of LLLT on hepatic fibrogenesis in animals subjected to BDL.Methodology: Adult male Wistar rats will be anesthetized and subjected to laparotomy for BDL. The control group (Sham) will undergo the same procedure without bile duct ligation. To evaluate the healing effect, laser application will occur daily after 7 days of BDL surgery, for 7 (BDL-post-7d) or 14 days (BDL-post-14d), when liver perfusion will be performed.Inflammation will be evaluated by measuring the activities of aspartate aminotransferase and alanine aminotransferase in the serum of rats at the end of the treatment, as well as by cytokine levels. Hepatic fibrogenesis will be assessed in tissue stained with Picrus Sirius, through morphometric analysis and collagen deposition profile by polarized light microscopy. Additionally, immunophenotyping will be performed by flow cytometry. Cell death and liver regeneration will also be evaluated by immunodetection for caspase-3 and Ki-67, respectively. This study represents a significant technological contribution compared to the current state-of-the-art. Currently, therapies for hepatic fibrosis are limited to removing the causative agent or, in advanced stages, liver transplantation. LLLT, being a non-invasive, drug-free, and safe modality, is a promising alternative for the treatment of liver diseases.