Fig. 2

OA-RD17 promoted macrophage polarization to reduce inflammation and epidermal regeneration to accelerate deep second-degree burn healing in mice. A Representative images of deep second-degree burn wound recovery on days 0, 4, 8, 12, and 14 in mice locally treated with PBS, rh-bFGF (100 ng/mL), or OA-RD17 (1 nM). B Quantification of deep second-degree burn wound repair on days 4, 8, 12, and 14 in mice. C Representative H&E staining of deep second-degree burn wounds on days 4, 8, and 14 after treatment with PBS (vehicle), rh-bFGF (100 ng/mL), or OA-RD17 (1 nM) in mice. Yellow dotted lines represent areas of neoepithelium; Es: eschar; NE: neoepithelium; GT: regenerated granulation tissue; Yellow arrows represent quantified areas of regenerated granulation tissue; scale bar 200 μm. D-F Quantification of regenerated epidermal scores, regenerated epidermal thickness, and regenerated granulation tissue in burned skin areas in mice. G Representative images of Ki67 immunohistochemical staining of regenerated epidermis in wound area on days 8 and 14 after treatment with PBS, rh-bFGF (100 ng/mL), or OA-RD17 (1 nM). Red arrows indicate positive staining, scale bar 50 μm. H Quantification of Ki67 expression in regenerated epidermis of wound area on days 8 and 14. I Representative images of immunohistochemical staining of inflammatory factor IL-1β in wound area on days 8 and 14 after treatment with PBS, rh-bFGF (100 ng/mL), or OA-RD17 (1 nM). Red arrows indicate positive staining, scale bar 50 μm. J Quantification of IL-1β expression in wound area; positive expression is defined as intensity of positive staining per unit area. All data are expressed as mean ± SEM from three independent experiments performed in quintuplicate; ns, no significance, *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001 indicate statistically significant difference compared to vehicle