Level of Nitric Oxide in Bronchoalveolar Lavage Fluid of Asthmatic Mice Model

Abstract

<span><b>Background</b>: </span> <span><span><span>Asthma is a chronic inflammatory disease with multifactorial and complicated</span></span></span> <span>mechanisms. Elevated level of exhaled Nitric Oxide (NO) in asthma and other inflammatory</span> <span>lung diseases has led to many studies examining NO as a potential marker of airway inflammation.</span> <span><br/><b>Objective</b>: </span> <span><span><span>This study was designed to determine the level of NO in Bronchoalveolar Lavage</span></span></span> <span>(BAL) fluid during early and late stages of asthmatic attack in mouse model. </span> <span><span><span><br/><b>Methods</b>: </span></span></span><span><span><span>In</span></span></span> <span>this study male BALB/c mice were used. The level of NO was determined in BAL fluid of</span> <span>asthmatic mice five minutes, six and sixteen hours after challenge with methacholine, as irritant</span> <span>and smoke and 5% ovalbumin as allergens, using colorimetric assay. </span> <span><span><span><br/><b>Results</b>: </span></span></span><span><span><span>The level of NO</span></span></span> <span>increased upon exposure to all three irritants used in this study (52.3 </span> <span><span lang="JA"><span lang="JA">μ</span></span><span><span>M for smoke and 49.5</span></span></span> μ <span><span>Mfor methacholine) as compared to 22.8 </span></span><span style="font-family: SymbolMT; font-size: medium;" lang="JA"><span style="font-family: SymbolMT; font-size: medium;" lang="JA">μ</span></span><span><span>M for the baseline. Our results showed that NO levels</span></span> were increased during early phase of asthmatic condition and reached to its maximum level after six hours and decreased at the late stage of asthma (16hrs) possibly by activating a feedback regulatory loop. In addition, high level of NO led to the hypertrophy of smooth muscle that can account for the pathological changes associated with asthma. <span><span><br/><b>Conclusion</b>: </span></span><span><span>Thus, NO is an</span></span> inflammatory marker in asthma and its measurement, as a non-invasive method during asthmatic attack is suggested. A careful development of specific inhibitors for iNOS enzyme during asthmatic attack is also necessary.