Among the genes and related biological pathways that we tested, no such drastic changes in the TLR signaling pathway was found in the ALI rats induced by either LPS (Table 2) or hypoxia (Table 3) alone as it was induced by combined LPS and hypoxia (Table 4), suggesting that hypoxia and LPS have synergistic effects on the TLR signaling pathway and that TLR4 plays a crucial role in bridging the interaction between hypoxia and inflammation. Here, TLR4 is linked to acute respiratory distress syndrome.