The effects of ML 3000 on antigen-induced responses in sheep

ML 3000 is a dual inhibitor of cyclooxygenase (COX) and 5-lipoxygenase (5-LO), two enzymes that contribute to the airway inflammation in asthma. When administered as an aerosol at a dose of 100 mg, 0.5 h before antigen challenge in allergic sheep, ML 3000 provided significant inhibition against the early bronchial response (EAR, mean 33% protection, P<0.05), completely blocked the late antigen-induced bronchoconstriction (LAR, mean 81% protection, P<0.05) and the airway hyperresponsiveness (AHR, P<0.05) to aerosolized carbachol that occurs 24 h after antigen challenge in this model. Consistent with this functional protection was a small but significant reduction in the percentage of neutrophils recovered in bronchoalveolar lavage (BAL) at 8 h and 24 h after challenge. These findings are similar to previous data obtained in this animal model with other 5-LO inhibitors (blockade of the LAR and AHR) and COX inhibitors (blockade of AHR). These results suggest that aerosol administration of a dual inhibitor of COX and 5-LO may have beneficial effects in the treatment of allergic airway disease. (C) 1997 Academic Press Limited.