EFFECTS OF CHOLINERGIC FUNCTION DEFICIENCY ON PULMONARY MECHANICS AND HISTOPATHOLOGY IN AN EXPERIMENTAL MODEL OF ACUTE INFLAMMATION INDUCED BY LPS INSTILLATION IN GENETICALLY MODIFIED MICE

• Grant number: 10/13363-6
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): March 01, 2012
• Effective date (End): August 31, 2013
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Carla Máximo Prado
• Grantee: Nathalia Montouro Pinheiro Menegasso
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Acute lung injury (ALI) is characterized by extensive lung inflammation, polymorphonuclear cells recruitment and release of proinflammatory mediators. It is a serious condition that develops with death in approximately 40% of cases. Despite several studies that have elucidated the pathophysiology of ALI, the treatment is still unsatisfactory. The cholinergic anti-inflammatory pathway was recently described in the lung and is related to a reflex via the vagus nerve that inhibits the release of inflammatory cytokines by stimulation of nicotinic receptors. Objective: To evaluate the effects of cholinergic deficiency in the lung mechanics and histopathological changes induced pulmonary instillation of lipopolysaccharide (LPS). Methodology: We will use genetically modified male mice that have a reduction in VAChT protein expression, which is associated with a decrease in acetylcholine release. These animals will be divided according to their genotyping in heterozygous (HET), homozygous (HOM) and wild type (WT) and will receive intranasal instillation of LPS 24 hours before the experimental protocol. We will evaluate: respiratory mechanics, lung inflammation via BAL and macrophage and neutrophil response in the lung tissue, the extracellular matrix remodeling, by assessing the content of collagen and elastic fibers, the expression of TNF-alpha and oxidative stress means of quantifying the content of isoprostane PGF2. All histopathological parameters will be quantified by morphometry. We will analyzed by Western Blot in lung tissue to detect TNF-alfa and IL-8. To confirm the importance of the cholinergic system in this response, a group of animals homozygous + LPS for 15 days will be treated with acetylcholinesterase inhibitor. Statistical analysis is performed using the SigmaStat. Based on the literature and in our preliminar data, we hope that homozygotous animals present a worse in inflammatory response induced by LPS, confiming the role of cholinergic system