Diabetes induced cardiac fibrosis. (A) The red color of Sirius red staining under the common microscope indicates total collagen deposition, representative images are from NC, NC + ALA, STZ and STZ + ALA (200 × magnification). (B) Type I and II collagen deposition were shown by orange and green color under the polarized light respectively, representative images are from NC, NC + ALA, STZ and STZ + ALA. (C) The protein level of type I and II collagen were determined by western blot, β-Actin was used as loading control. Bar graph, density analysis results from 8 rats per group. Results are mean values ± standard deviation. *p < 0.05 vs Control group, #p < 0.05 vs. STZ group.