Negative-Pressure Wound Therapy Induces Lymphangiogenesis in Murine Diabetic Wound Healing

Background: Decreased lymphangiogenesis contributes to impaired diabetic wound healing. Although negative-pressure wound therapy (NPWT) has been shown to be effective in the treatment of recalcitrant wounds, its impact on lymphangiogenesis remains to be elucidated. In this study, the authors investigate the mechanisms of lymphangiogenesis following NPWT treatment of diabetic murine wound healing. Methods: Full-thickness dorsal skin wounds (1 x 1 cm(2)) were excised on 30 db/ db mice. The mice were either treated with occlusive covering (control group, n = 15), or received a 7-day treatment of continuous NPWT at -125 mmHg (NPWT group, n = 15). The wounds were photographed on days 0, 7, 10, 14, 21, and 28. Wound tissue was harvested on days 10, 14, 21, and 28 for quantitative analysis. Functional analysis of lymphatic drainage was performed on days 14 and 28 with Evans blue dye tracing. Results: Lymphatic density and diameter, as visualized through podoplanin probing, was significantly higher in the NPWT group compared to the control group (P < 0.001). NPWT up-regulated the expression of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) at the protein level (P = 0.04), and significant differences were noted in lymphatic density as assessed by LYVE-1 staining (P = 0.001). Leukocyte infiltration was significantly higher in the NPWT group (P = 0.01). A higher speed of wound closure (P < 0.0001) and greater wound bed thickness (P < 0.0001) were noted in the NPWT group compared to the control group. Conclusions: NPWT increased the lymphatic vessel density and diameter with LYVE-1 up-regulation. NPWT therefore plays a positive role in lymphangiogenesis in diabetic wound healing.