PDGFRB and diabetes mellitus: The mean optical density of PDGFR-β positivity was quantified and was significantly lower in the DM and DH groups compared to the NC group (NC, 0.069 ± 0.009 vs. DM, 0.054 ± 0.002, P < 0.05; NC, 0.069 ± 0.009 vs. DH, 0.047 ± 0.009, P < 0.05; Figure 4D).