Oral Administration of Epigallocatechin Gallate Prevents Air Pollution‐Induced Acute Lung Injury in Mice Via the Induction of Antioxidants

Health hazards caused by air pollutants are increasing worldwide (SDGs 3.9), but no established prevention methods exist. Recently, we showed that intraperitoneal administration of epigallocatechin gallate (EGCG) prevents air pollutant-induced acute lung injury. To establish EGCG ingestion as a preventive method, the efficacy of oral EGCG administration needs to be analyzed, as it is easier than that of intraperitoneal administration. Therefore, we analyzed the effects of oral EGCG administration and ad libitum consumption of an EGCG-containing diet in mice. The combination of 0.2% EGCG-containing diet and oral EGCG administration (200 mg/kg) significantly inhibited the urban aerosol (UA)-induced acute lung injury, although each treatment alone was ineffective. Specifically, compared with the UA group, the combination group showed 37.3% decrease in total cell count, 30.5% decrease in neutrophil count, 52.6% decrease in protein level, and 39.6% decrease in dsDNA level in the bronchoalveolar lavage fluid. This combination also significantly inhibited air pollutant-induced increases in proinflammatory cytokine and chemokine expression (e.g., tumor necrosis factor-α) and ROS production in mouse lungs. Moreover, this combination increased the expression of antioxidant factors, such as nuclear factor E2-related factor 2, in whole blood. Thus, this EGCG-based intervention combination limits UA-induced acute lung injury by increasing antioxidant expression. SUMMARY: The effects of a combination of EGCG-based interventions were analyzed. The combination prevented air pollutant-induced lung inflammatory responses. The combination suppressed air pollutant-induced ROS production in the lungs. The combination increased the expression of various antioxidants in whole blood.