Negative-Pressure Wound Therapy Enhances Local Inflammatory Responses in Acute Infected Soft-Tissue Wound

Abstract

Clinical studies found that negative-pressure wound therapy (NPWT) displayed significant clinical benefits in the healing of infected wounds. However, the effect of NPWT on local inflammatory responses in acute infected soft-tissue wound has not been investigated thoroughly. The purpose of this study was to test the impact of NPWT on local expression of proinflammatory cytokines, amount of neutrophils, and bacterial bioburden in wound from acute infected soft-tissue wounds. Full-thickness wounds were created on the back of rabbits, and were inoculated with Staphylococcus aureus strain ATCC29213. The wounds were treated with sterile saline-moistened gauze dressings and NPWT with continuous negative pressure (-125 mmHg). Wound samples were harvested on days 0 (6 h after bacterial inoculation), 2, 4, 6, and 8 at the center of wound beds before irrigation for real-time PCR analysis of gene expression of IL-1β, IL-8, and TNF-α. Wound biopsies were examined histologically for neutrophil quantification in different layers of tissue. Quantitative bacterial cultures at the same time point were analyzed for bacterial clearance. Application of NPWT to acute infected wounds in rabbits was compared with treatment with sterile saline-moistened gauze, over an 8-day period. NPWT-treated wounds exhibited earlier and greater peaking of IL-1β and IL-8 expression and decrease in TNF-α expression over the early 4 days (P < 0.05). Furthermore, histologic examination revealed that significantly increased neutrophil count was observed in the shallow layer in wound biopsies of NPWT treatment at day 2 (P < 0.001). In addition, there was a statistically significant decrease of bacteria load from baseline (day 0) at days 2 and 8 in NPWT group (P < 0.05). In conclusion, this study demonstrates that NPWT of acute infected soft-tissue wounds leads to increased local IL-1β and IL-8 expression in early phase of inflammation, which may trigger accumulation of neutrophils and thus accelerate bacterial clearance. Meanwhile, the success of NPWT in the treatment of acute wounds can attenuate the expression of TNF-α, and the result may partly explain how NPWT can avoid significantly impairing wound healing.

The effectiveness of negative pressure therapy on infected wounds: preliminary results

“…Furthermore, continuous cleaning of the wound can reduce the bacterial load in the wound and removes inflammatory mediators that inhibit healing. Interestingly, a study published by Liu D et al (22) showed an increase of the expression of the genes of the IL-1β and IL-8 in the early stages of inflammation and a decrease in those of TNF-α in full-thickness dorsal ulcers in rabbit models. The ulcer model was inoculated with a known strain of Staphylococcus aureus, and NPWT was applied.…”

Negative pressure wound therapy inhibits inflammation and upregulates activating transcription factor‐3 and downregulates nuclear factor‐κB in diabetic patients with foot ulcerations

“…It is the delivery of subatmospheric pressure by a vacuum pump to keep a sealed environment that is connected to an open‐pore foam and a dressing covered with an adhesive drape . A great many studies have reported that the reason why NPWT accelerates wound healing was that it could attenuate the expression of inflammatory cytokines such as tumor necrosis factor α (TNF‐α) in the wound . However, the precise physiological mechanism by which NPWT suppresses inflammation is still unclear.…”

Improvement of wound healing by regulated oxygen-enriched negative pressure-assisted wound therapy in a rabbit model

“…of markedly higher IL‐8 levels in wound fluids during vacuum‐assisted closure therapy . Liu et al . reported that increased local IL‐1β and IL‐8 expression in the early phase of inflammation may trigger accumulation of neutrophils.…”