Glutathione attenuates diesel exhaust-induced lung epithelial injury via NF-κB/Nrf2/GPX4-mediated ferroptosis

Abstract

Diesel exhaust (DE) emissions pose a significant threat to public health. This study linked DE-mediated reactive oxygen species (ROS) and ferroptosis with lung epithelial disruption, also the protective potential of exogenous glutathione (GSH) administration was investigated. C57BL/6 mice were divided into three groups: filtered air (control), DE exposed, and DE+GSH (administered intranasally on alternate days). Airway hyperresponsiveness (AHR), lung tissues, and bronchoalveolar lavage fluid (BALF) were used for analysis. DE exposure significantly impaired lung function parameters as shown by AHR. Elevated ROS depleted the GSH/GSSG ratio and suppressed Nrf2 activity, disrupting antioxidant defense mechanisms, which were restored by GSH administration. DE-induced ROS acted as a key driver of ferroptosis, characterized by suppressed SLC7411 expression thereby decreased GSH synthesis and GPX-4 activity, inducing lipid peroxidation. Ferroptosis was significantly mitigated by increased GSH pool, which restored GPX-4 levels and reduced lipid peroxidation. Concurrently, DE induced ROS promoted DNA damage and apoptosis in lung epithelial cells wherein GSH treatment preserved cell survival in DE exposed mice. The heightened DE-associated ROS further amplified inflammation, as shown by increased cytokines (TNF-α, IL-6, TSLP, IL-33) and P-NF-κB activation. Activated inflammatory cascade disrupted tight junction proteins (claudins, occludin), resulted in weakened epithelial barrier and increased permeability. Lung barrier disruption was evidenced by transmission electron microscopy and immunohistochemistry, corroborated with elevated albumin levels. GSH effectively restored tight junction integrity and preserved barrier function in DE+GSH mice lungs. In conclusion, DE-induced oxidative stress and ferroptosis-triggered inflammation compromised epithelial barrier promoting lung injury. Exogenous GSH administration showed potential in restoring DE-associated lung damage.