Curcumin protects BEAS‑2B cells from PM2.5‑induced oxidative stress and inflammation by activating NRF2/antioxidant response element pathways

Fine particulate matter (PM_2.5) with an average aerodynamic diameter of <2.5 µm can cause severe lung injury. Oxidative stress and inflammation are considered the main outcomes of PM_2.5 exposure. Curcumin is a well‑known antioxidant; however, its effect on PM_2.5‑induced oxidative injury in airway epithelial cells remains unclear. In the present study, it was demonstrated that pre‑treatment with curcumin significantly reduced the PM_2.5‑induced apoptosis of BEAS‑2B human bronchial epithelial cells by decreasing the level of intercellular reactive oxygen species. Western blot analysis revealed that curcumin increased the expression of nuclear factor erythroid 2‑related factor 2 (NRF2) and regulated the transcription of downstream genes, particularly those encoding antioxidant enzymes. Moreover, curcumin reduced the PM_2.5‑induced expression and production of inflammatory factors, and induced the expression of the anti‑inflammatory factors, interleukin (IL)‑5 and IL‑13. Taken together, the present study demonstrates that curcumin protects BEAS‑2B cells against PM_2.5‑induced oxidative damage and inflammation, and prevents cell apoptosis by increasing the activation of NRF2‑related pathways. It is thus suggested that curcumin may be a potential compound for use in the prevention of PM_2.5‑induced tissue injury.