Methods: Mice were divided into control (CON) and allergen sensitized (SEN) groups. SEN was sensitized with ovalbumin (OVA) on days 1 and 6 (30?μg; i.p.), followed by 5% OVA aerosol challenge (days 11–13). Treatments included (a) losartan (SEN?+?LOS; 20?mg/kg i.p., day 14), (b) novokinin (SEN?+?NOV; 0.3?mg/kg i.p., day 14), and (c) PD 123319 (SEN?+?PD; 5?mg/kg i.p., day 14). Experiments for airway responsiveness, bronchoalveolar lavage, and tracheal ring reactivity using isolated organ bath were performed.
Results: Airway responsiveness to methacholine (MCh) (48?mg/mL) was significantly higher in SEN (563.71?±?40% vs. 294.3?±?123.84 in CON). This response was potentiated in SEN?+?PD group (757?±?30%; p?<?.05 compared to SEN). SEN?+?LOS (247.61?±?86.85%) and SEN?+?NOV (352?±?11%) had significantly lower response compared to SEN. SEN?+?LOS (26.22?±?0.29%) and SEN?+?NOV (46.20?±?0.76%) treatment significantly (p?<?.001) attenuated total cell count and eosinophils compared to SEN group (69.38?±?1.5%), while SEN?+?PD (73.04?±?0.69%) had highest number of eosinophils. Tracheal response to MCh was significantly higher in SEN group compared to controls, and this response was significantly lowered with the losartan and novokinin treatments.
Conclusions: These data suggest that AT1 and AT2 receptors have opposite effects in modulating airway hyperresponsiveness and inflammation in asthma. 相似文献