TLR4 and diabetes mellitus: As shown in Figures 5F–J, the mRNA expression of TLR4, IRAK1, TRAF6, NF-κB, and collagen I was increased in DM rats and downregulated in DM + DAPA group (TLR4: 0.8798 ± 0.1681 vs. 1.829 ± 0.4619 vs. 0.3664 ± 0.1717, P < 0.0001; IRAK1: 0.9381 ± 0.2163 vs. 1.472 ± 0.3509 vs. 0.4934 ± 0.1929, P = 0.0003; TRAF6: 1.032 ± 0.2877 vs. 2.071 ± 0.5725 vs. 1.407 ± 0.4928, P = 0.0151; NF-κB: 1.014 ± 0.1856 vs. 1.580 ± 0.5045 vs. 0.6292 ± 0.1899, P = 0.0017; collagen I: 0.6919 ± 0.2063 vs. 2.144 ± 0.6320 vs. 1.394 ± 0.3283, P = 0.0013).