Isosinensetin alleviates the injury of human bronchial epithelial cells induced by PM2.5

Flavonoids which are extracted from citrus peel and pulp have been reported to have multiple beneficial effects on human health. Isosinensetin (ISO) is a type of flavonoid compound, which has several protective effects including anticancer, antioxidant, antiviral, anti‑inflammatory and bacteriostatic. However, the molecular mechanism of its antioxidant and anti‑inflammatory effects remain unclear. The present study aimed to investigate the intervention effect and possible mechanism of ISO on human bronchial epithelial cells injured by fine particular matter ≤2.5 µm in diameter (PM2.5). In the present study, the cell viability was detected by Cell Counting Kit‑8 method. The levels of pro‑inflammatory cytokines were analyzed by ELISA. The level of reactive oxygen species (ROS) was detected by fluorescence probe. The expression levels of proliferating cell nuclear antigen (PCNA), nuclear factor erythroid 2‑related factor 2 (Nrf2) and nuclear factor кΒ (NF‑кB) proteins were detected by western blotting. The results revealed that ISO evidently increased the viability of 16‑HBE cells and sharply decreased the levels of pro‑inflammatory factors in cell culture supernatant. ISO significantly inhibited ROS release caused by PM2.5. Moreover, the expression levels of PCNA, Nrf2 and NF‑кB proteins were downregulated after ISO incubation. These results indicated that ISO alleviated 16‑HBE‑cell injury by PM2.5 through the ROS‑Nrf2/NF‑кB signaling pathway.