Effects of tranilast and pentoxifylline in a mouse model of chronic asthma using house dust mite antigen

Tranilast has been used in allergic diseases because of its inhibitory effect on mast cells; it also has an anti-fibrotic effect in several diseases. Pentoxifylline (PTX), a methylxanthine derivative, is a potent anti-inflammatory drug that is known to manifest its effect through the inhibition of Th1 cytokine, but with an uncertain effect on Th2 cytokine. Seven-week-old female BALB/c mice were studied as a chronic asthma model. The mice were challenged with house dust mite (HDM) antigen for 7 weeks. Each group of mice was given an intraperitoneal injection of tranilast, PTX, or tranilast plus PTX before antigen administration. In this mouse model of chronic asthma, tranilast, and PTX each had an inhibitory effect on airway remodeling as well as on airway hyperresponsiveness (AHR) and airway inflammation. The improved events of these drugs were related with the inhibition of the Th2 cytokine IL-13 and TGF-β 1. Immunohistochemical analysis showed that decreases in the peribronchial trichrome stained area in each treatment group were associated with improvements in the peribronchial smooth muscle hyperplasia, collagen type I, and collagen type III deposition. These drugs could have potential beneficial effects on chronic asthma, especially with respect to airway remodeling.