Potential molecular mechanisms of negative pressure in promoting wound healing

Negative pressure wound therapy (NPWT) has been widely used in various lesions. This study aimed to explore the biological effects of negative pressure on the polymorphonuclear neutrophils (PMNs), macrophages, and epidermal keratinocyte cells involved in wound healing. PMNs differentiated from HL-60, macrophages were derived from THP-1 monocytes, and keratinocytes were cultured in vitro, and they were treated with 0, -0.03 mp, and -0.05 mp, respectively. Cell ultrastructure; viability; apoptosis; and protein factors such as tumour necrosis factor-α (TNF-α), interferon-γ (IFN-γ), epidermal growth factor (EGF), epidermal growth factor receptor (EGFR), interleukin-17 (IL-17), and cell division cycle 42 (Cdc42) were determined by transmission electron microscopy (TEM), CCK8, flow cytometry (FCM), ELISA, and simple Western assays, respectively. After negative pressure stimulation, the cell ultrastructure of PMNs and macrophages cells was presented with a marked increase of lysosomes and a relative decrease of mitochondria. In addition, the cell viability was enhanced in PMNs and macrophages in a pressure-dependent manner and apoptosis ratios were significantly reduced in PMNs and macrophages. In addition, under -0.05 negative pressure, IFN-γ and IL-17 were significantly increased in PMNs or macrophages. Moreover, increased EGF and EGFR and Cdc42 levels in keratinocytes induced by the -0.05 mpa were detected, indicating that the migration chemotaxis of keratinocyte cells was enhanced. Negative pressure might promote cell proliferation, accelerate inflammatory responses, and promote epithelialisation during wound healing by increasing IFN-γ, IL-17, Cdc42, EGF, and EGFR in PMNs, macrophages, or keratinocytes under different negative pressures.