The Effects of Breathing Patterns on Expression of Inflammatory Factors and Increasing Airway Responsiveness in the Rats

Asthma is a common chronic respiratory disease with reversible narrowing of the airways. Evidences suggest breathing patterns can involve in increasing airway resistance and airway remodeling. Also, the abnormal muscle may be the cause of airway hyper-responsiveness and inflammation. The aim of this study was to evaluate the effect of breathing patterns on resistance, airways responsiveness to methacholine and expression of IL-8 and TNF-α in lung tissues of the rats. Using ventilator, three different breathing patterns including ventilation with constant volume and respiratory rate, normal breathing pattern and asthma breathing pattern were induced in three separate groups of animals. Airway resistance was measured after 60 minute ventilation and after intra-peritoneal injection of 1, 4, and 16 μg/kg methacholine. The expression of TNF-α and IL-8 levels in lung tissue were measured after ventilation by real-time PCR technique. There were significant increasing in airway resistance (p<0.05), whereas there were no significant differences in TNF-α and IL-8 expression among the groups (p>0.05). Applying different respiratory patterns in similar inflammatory conditions can cause changes in resistance and responsiveness of airway to methacholine.