Biomarkers for oxidative stress in acute lung injury induced in rabbits submitted to different strategies of mechanical ventilation

• Grant number: 12/03458-5
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: April 01, 2012
• End date: September 30, 2012
• Field of knowledge: Health Sciences - Medicine - Maternal and Child Health
• Principal Investigator: José Roberto Fioretto
• Grantee: José Roberto Fioretto
• Host Institution: Faculdade de Medicina (FMB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Oxidative damage has been said to play an important role in pulmonary injury, which is associated with the development and progression of acute respiratory distress syndrome (ARDS). We aimed to identify biomarkers to determine the oxidative stress in an animal model of acute lung injury (ALI) using two different strategies of mechanical ventilation. Rabbits were ventilated using either conventional mechanical ventilation (CMV) or high-frequency oscillatory ventilation (HFOV). Lung injury was induced by tracheal saline infusion (30mL/kg, 38ºC). In addition, five healthy rabbits were studied for oxidative stress. Isolated lymphocytes from peripheral blood and lung tissue samples were analyzed by alkaline single cell gel electrophoresis (comet assay) to determine DNA damage. Total antioxidant performance (TAP) assay was applied to measure overall antioxidant performance in plasma and lung tissue. HFOV rabbits had similar results to healthy animals, showing significantly higher antioxidant performance and lower DNA damage compared to CMV in lung tissue and plasma. TAP showed a significant positive correlation (r=0.58; p=0.0006) in plasma and lung tissue. In addition, comet assay presented a significant positive correlation (r=0.66; p=0.007) between cells recovered from target tissue and peripheral blood. Moreover, antioxidant performance was significantly and negatively correlated with DNA damage (r= -0.50; p=0.002) in lung tissue. This study indicates that both TAP and comet assay identify increased oxidative stress in CMV rabbits compared to HFOV. Antioxidant performance analyzed by TAP and oxidative DNA damage by comet assay, both in plasma, reflects oxidative stress in the target tissue, which warrants further studies in humans. (AU)