N-Acetylcysteine and Its Therapeutic Potential in an Animal Model of Allergic Asthma.

Background: N-acetylcysteine (NAC) is a classical mucolytic agent that, in addition to its mucolytic activity, also exhibits antioxidant activity. This could be beneficial in treating chronic inflammatory airway diseases, including asthma. Background: We evaluated the ability of NAC to modulate airway defense mechanisms, airway reactivity, inflammation, and remodeling after 10 days of administration [20 and 60 mg/(kg·d)] in an experimental guinea pig model of allergic inflammation. Methods: The concentrations of inflammatory cytokines (interleukins: IL-4, IL-5, IL-10, IL-12, and IL-13), granulocyte macrophage-colony stimulating factor (GM-CSF), interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) were measured in bronchoalveolar lavage fluid using a multiplex detection method. The concentration of remodeling marker transforming growth factor beta-1 (TGF-β1) was measured in lung homogenates using enzyme-linked immunosorbent assay. In vivo, changes in specific airway resistance and number of cough efforts were determined. Tracheal smooth muscle reactivity was evaluated in vitro. Ciliary beat frequency (CBF) indicated mucociliary clearance. Results: A 10-day administration of NAC at a higher dosage led to a significant decrease in the regulatory cytokines IL-4, IL-5, and GM-CSF. NAC, in both dosing schedules, decreased the levels of TGF-β1. NAC at a higher dosage reduced the number of chemically induced cough reflexes and CBF. NAC did not affect airway hyperreactivity parameters. Conclusion: NAC is a multifactorial drug, and under our experimental conditions of allergic inflammation, it showed positive effects on the levels of regulatory cytokines and growth factors, which probably led to a reduction in the intensity of airway defense mechanisms.