Inhaled budesonide inhibits OVA-induced airway narrowing, inflammation, and cys-LT synthesis in BN rats

The objective of the present investigation was to examine the effects of an inhaled glucocorticoid, budesonide, on antigen-induced production of cyste inyl leukotrienes (cys-LTs) and pulmonary inflammatory cell infiltration in the Brown Norway rat, an animal model of asthma. Two weeks after sensitiza tion to ovalbumin, rats were treated with budesonide (2.5 mg/kg) 18 and Ih before challenge with antigen. Budesonide abolished the late response to ov albumin (P < 0.02) and strongly inhibited the in vivo synthesis of N-acetyl -leukotriene E-4, an indicator of cys-LT synthesis, during this period (P < 0.005). Both total bronchoalveolar lavage (BAL) cells (P < 0.01) and BAL m acrophages (P < 0.005) were markedly reduced to similar to 25% of their con trol levels after treatment with budesonide. It can be concluded that inhib ition of the antigen-induced late response in Brown Norway rats by budesoni de is associated with reductions in both BAL macrophages and cys-LT synthes is. It is possible that the effect of budesonide on cys-LT synthesis is rel ated to its effects on pulmonary macrophages.