Effects of the P2RX4 antagonist BR11595 in a guinea pig model of chronic asthma

Background and Purpose

Asthma is characterized by airway hyperresponsiveness (AHR), allergic inflammation, and airway remodelling. Although recent studies have shown that asthma pathophysiology involves P2X4 receptor activation, a potential link with chronic asthma remains to be explored. We investigated the effect of a novel P2X4 receptor antagonist BR11595 on allergen-induced airway responses in a guinea pig model of chronic asthma.

Experimental Approach

Sensitized guinea pigs were exposed to saline or ovalbumin (OVA) once weekly via aerosolization for 12 weeks. BR11595 (10 mg·kg⁻¹) was injected intraperitoneally five times per week, for four different regimens: all 12 weeks, first 6 weeks, last 6 weeks, or last week only. Airway responsiveness to histamine was assessed 24 h before and 6 h after OVA exposure in weeks 1, 6, and 12. Lung tissue inflammation and remodelling were determined 24 h after the last OVA exposure.

Key Results

OVA induced AHR at weeks 1, 6, and 12 compared with saline-challenged animals. The AHR was less pronounced in week 12 compared with week 1. BR11595 significantly reduced OVA-induced AHR in week 6 in guinea pigs treated with BR11595 for 6 weeks. AHR in week 12 was reduced after BR11595 treatment in week 12 only, next to OVA-induced eosinophilia and Goblet cell hyperplasia, indicating an acute role of P2X4 receptors on chronic inflammation.

Conclusion and Implications

The P2X4-receptor antagonist BR11595 acutely inhibits AHR, eosinophilia, and Goblet cell hyperplasia after 12 weeks, indicating its potential as a therapeutic target for acute intervention of chronic asthma attacks or exacerbations.