Abstract
Airway inflammatory diseases, such as asthma, are a global public health concern owing to their chronic inflammatory effects on the respiratory mucosa. Molecular hydrogen (H(2)) has recently been recognized for its antioxidant and anti-inflammatory properties. In this study, we examined the therapeutic potential of H(2) in airway inflammation using an ovalbumin (OVA)-induced BALB/c mouse model of allergic asthma. Female BALB/c mice were sensitized and challenged with OVA to induce airway inflammation, and 30 mice were randomly divided into five groups: NT (non-treatment), HTC (3% H(2) treatment only), NC (negative control, OVA only), PC (positive control, OVA + intranasal 1 mg/mL salbutamol 50 μL), and HT (H(2) treatment, OVA + inhaled 3% H(2)). Various inflammatory and oxidative stress (OS)-induced markers such as white blood cells (WBCs) and their differential counts, lung histology, cytokine levels such as interleukin (IL)-4, (IL)-5, (IL)-13, interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), granulocyte-macrophage colony-stimulating factor (GM-CSF), (IL)-10, reactive oxygen species (ROS), nitric oxide (NO), glutathione peroxidase (GPx), and catalase (CAT), and total immunoglobulin E (IgE) levels were investigated. Our results showed that inhaled H(2) significantly reduced inflammatory cell infiltration, OS markers, and pro-inflammatory cytokine expression while upregulating antioxidant enzyme activity. Furthermore, H(2) also significantly decreased serum IgE levels, a marker of allergic inflammation. Collectively, our findings suggest that H(2) inhalation is a promising treatment option for airway inflammation, offering a novel approach with potential clinical applications.