Animal experiment:

Male mice (9 weeks old, 33 to 42g are used) BLM solution (15 mg/mL) is intravenously injected into mice (0.1 mL/10 g of body weight) on day 0. Mice are sacrificed on day 7 or 21. They are exposed to an aerosol of KP496 (KP-496) solution (0.5%) for 30 min using a pressure nebulizer 1 h before and 3 h after BLM-injection on day 0. From day 1 to the day before sacrificed, mice are exposed to KP496 (0.5%) for 30 min morning and evening[1].

KP496 is a selective, dual antagonist for Leukotriene D4 receptor and Thromboxane A2 receptor.

KP496 significantly inhibits acute (day 7) and chronic (day 21) lung inflammation. KP496 attenuates the number of lymphocytes on day 7 and those of macrophages, neutrophils, and eosinophils on days 7 and 21. KP496 and prednisolone significantly suppress the increase of hydroxyl-L-proline content in the lung. Compare to respective vehicle control group, the inhibition ratio of KP496 and prednisolone for increase of hydroxyl-L-proline content is about 74 and 63%, respectively[1]. The KP496 (100 mg/head) group and prednisolone (10 mg/kg) group exhibit significant inhibition of numbers of infiltrating total cells, eosinophils, monocytes/macrophages, and lymphocytes compare with the control group. Infiltration of all types of cells except neutrophils is decreased in the KP496 (30m g/head) group, though not to significant extents[2].

[1]. Kurokawa S, et al. Effect of inhaled KP-496, a novel dual antagonist of the cysteinyl leukotriene and thromboxane A2 receptors, on a bleomycin-induced pulmonary fibrosis model in mice. Pulm Pharmacol Ther. 2010 Oct;23(5):425-31. [2]. Ishimura M, et al. Effects of KP-496, a novel dual antagonist for cysteinyl leukotriene receptor 1 and thromboxane A2 receptor, on Sephadex-induced airway inflammation in rats. Biol Pharm Bull. 2009 Jun;32(6):1057-61.