During the process of ALI, there are three main pathways (NF-E2 related factor 2/Kelch-like ECH-associated protein 1, Toll-like receptor-4 and NOD-like receptor protein 3) that play an important role, but these pathways all involve the signals of NF-κB (Yue and Chen, 2019). Here, TLR4 is linked to acute respiratory distress syndrome.