Negative pressure wound therapy promotes wound healing by down-regulating miR-155 expression in granulation tissue of diabetic foot ulcers

Abstract

Our study aims to investigate the effect of negative pressure wound therapy (NPWT) on microRNA-155 (miR-155) in the granulation tissue of patients suffering from diabetic foot ulcers (DFUs) and its correlation with wound healing. A total of sixty patients diagnosed with DFUs were randomly assigned to either the NPWT group (n = 40) or the Non-NPWT group (n = 20) in a 2:1 ratio. After debridement, the NPWT group received NPWT treatment for one week, while the Non-NPWT group underwent routine dressing therapy. The expression of miR-155 in DFU granulation tissues was evaluated by qRT-PCR before and after treatment for one week. Following termination, wound healing rates were assessed in the NPWT group, and the correlation between variations in miR-155 expression (ΔmiR-155) and wound healing was analyzed pre and post NPWT treatment. In vitro experiments were conducted to investigate the effects of negative pressure on variations of miR-155 expression, as well as proliferation, migration, and apoptosis in normal human dermal fibroblasts (NHDFs). The NPWT group showed a decrease in miR-155 expression in wound granulation tissue compared with pre-treatment [4.12 (1.22, 14.85) vs. 6.83 (2.15, 15.72), P < 0.05]. Conversely, there was no statistically significant difference in miR-155 expression in wound granulation tissue between pre-treatment and post-treatment in the Non-NPWT group (P > 0.05). However, analysis revealed a positive correlation between ΔmiR-155 and wound healing rate after 4 weeks in the NPWT group (χ2 = 4.829, P = 0.028). The in vitro experiments showed a significant decrease in miR-155 expression in NHDFs under negative pressure measured at -125 mmHg (P < 0.05). This reduction in miR-155 expression, in turn, enhanced the proliferation and migration ability while decreasing the apoptosis rate of NHDFs by targeting the upregulation of fibroblast growth factor 7 (FGF7) gene expression (P < 0.05). It is concluded that NPWT promotes DFU healing by reducing the expression of miR-155 in granulation tissue and the efficacy of NPWT correlated with altered miR-155 expression in wound tissue.