In addition, ELISA demonstrated that the serum and BALF levels of RAGE, TGF-β1, MMP2, and MMP9 in the ARDS group were 8.02 ± 1.7, 4.16 ± 0.49, 2.87 ± 0.29, and 2.13 ± 0.12 times (for sera) and 10.70 ± 1.36, 5.38 ± 0.87, 2.93 ± 0.24, and 2.76 ± 0.24 times (for BALF) higher than those in the control group (P < 0.05 in all cases). Here, MMP9 is linked to acute respiratory distress syndrome.