Histopathological evaluations of a wound bed from a db/db mouse treated with PDGF-BB for 10 days and harvested 11 days after wounding.

<p>Scale Bars = 500 µm. (<b>A</b>) Measurement of epithelial gap (dotted black line) and reepithelialization (dotted red lines). The epithelial gap was defined as the distance between the advancing edges of keratinocyte migration measured in millimeters. Length of reepithelialization was defined as the length of the layer of proliferating keratinocytes covering the wound area. This value was obtained by measuring s the distance between the free edge of the keratinocyte layer and the base where the cells were still associated with native, non-affected dermal tissue (*). The black vertical lines denote the area of separation between the pre-existing collagen and wound bed. The final value was the sum of distance in millimeters of both sides. H&E staining. (<b>B</b>) Inflammatory infiltrate in the wound bed. The inflammatory response was assessed using a semi-quantitative scoring system ranging from 0 to 4 where 0 indicates no inflammation, 1 indicates 0–25% of the wound area affected, 2 indicates 25–50% of the wound area affected, 3 indicates 50–75% of the wound area affected, and 4 indicates >75% of the wound area affected. This sample was classified as score 2. H&E staining. (<b>C, D and E</b>) Measurement of the fibrovascular dermal proliferation in the wound bed. Picrosirius red staining. (<b>C</b>) The wound bed area is outlined (green lines), comprising a preset depth of 0.75 mm (this is the average depth of the wounds in the experiment) and the borders between preexisting dermal collagen and newly formed collagen. (<b>D</b>) Under polarized light the bright collagen fibers of the wound bed are highlighted and automatically measured by the software (<b>E</b>), and the final data is expressed as a percentage of outlined wound area.