MMP9 and acute respiratory distress syndrome: Western blot analysis of homogenized rat lung tissue showed that, compared to those of the control group, the protein levels of RAGE (Figure 5(a)), TGF-β1 (Figure 5(b)), MMP2 (Figure 5(c)), and MMP9 (Figure 5(d)) in the lung tissues of the ARDS group increased by 1.54 ± 0.05, 2.87 ± 0.07, 2.44 ± 0.12, and 6.38 ± 1.27 times, respectively, while those of the ARDS + SIS3 group decreased by 19.34 ± 1.74, 63.10 ± 1.89, 57.90 ± 4.97, and 81.78 ± 2.09% compared to that of the ARDS group, respectively (P < 0.05 in all cases).