Methods: We compared airway inflammation and hyperresponsiveness, as well as arginase expression, using NOS or arginase inhibitors in 6-week-old female C57BL/6, and NOS-2 knockout mice.
Results: Airway hyperresponsiveness was unaffected by NOS-2 depeletion or NOS inhibition. However, airway inflammation was aggravated in NOS-2 knockout mice than in wild-type mice with augmentation of arginase I expression. Inhibition of arginase attenuated airway inflammation in wild-type and NOS-2 knockout mice.
Conclusions: NOS-2 knockout mice showed increased ovalbumin-induced airway inflammation with augmentation of arginase I expression. Our results suggested that imbalance between NOS-2 and arginase with augmentation of arginase I expression resulted in aggravation of airway inflammation, and inhibitors of arginase I may be effective in suppressing allergic inflammation