The Lymphangiogenic Effect of Continuous Negative Pressure Wound Therapy in Murine Incisional Wounds

Abstract

INTRODUCTION: The effects of negative pressure wound therapy (NPWT) on the vascular system are well described. Despite the significant role of the lymphatics in wound healing, the impact of NPWT on lymphangiogenesis remains to be elucidated. Here, we studied the effects of NPWT on lymphatic regeneration in a murine incisional wound model. METHODS: Thirty diabetic mice (db/db) received dorsal incisional skin wounds and were treated with occlusive covering (Control, n = 15) or continuous NPWT (24 hours × 7 days, –125 mmHg; NPWT, n = 15). The wounds were monitored for 28 days, tissue was harvested on day 10 for analysis, and Evans Blue staining of lymphatic drainage was performed at 28 days. RESULTS: NPWT was associated with increased lymphatic density, as visualized using the lymphatic-vessel specific Podoplanin (39.6 ± 19.9 vs 11.5 ± 5.9 PDPN+/HPF; p < 0.001) and LYVE-1 (24.8 ± 9.1 vs 13.7 ± 7.9 LYVE-1+/HPF; p = 0.01). Lymphatic vessel diameter was higher in the NPWT group (27.5 ± 9.0 vs 12.4 ± 2.2 μm; p < 0.001). Western blotting showed that NPWT upregulated the expression of LYVE-1 at the protein level (p = 0.03). On functional assessment of the lymphatics, the NPWT exhibited a larger area of Evans Blue positivity at all timepoints (0, 5, 10, 15, 20, 25 and 30 minutes). CONCLUSION: Our findings indicate that NPWT significantly modulates lymphatic regeneration in incisional wounds. The effects were shown to occur at the protein level, resulting in structural and functional improvement. This highlights the potential of NPWT to therapeutical stimulate lymphatic growth and drainage in wound healing or in conditions such as lymphedema.