Effects of negative pressures on epithelial tight junctions and migration in wound healing

Abstract

Negative-pressure wound therapy has recently gained popularity in chronic wound care. This study attempted to explore effects of different negative pressures on epithelial migration in the wound-healing process. The electric cell-substrate impedance sensing (ECIS) technique was used to create a 5 × 10−4cm2wound in the Madin-Darby canine kidney (MDCK) and human keratinocyte (HaCaT) cells. The wounded cells were cultured in a negative pressure incubator at ambient pressure (AP) and negative pressures of 75 mmHg (NP75), 125 mmHg (NP125), and 175 mmHg (NP175). The effective time (ET), complete wound healing time ( Tmax), healing rate ( Rheal), cell diameter, and wound area over time at different pressures were evaluated. Traditional wound-healing assays were prepared for fluorescent staining of cells viability, cell junction proteins, including ZO-1 and E-cadherin, and actins. Amount of cell junction proteins at AP and NP125was also quantified. In MDCK cells, the ET (1.25 ± 0.27 h), Tmax(1.76 ± 0.32 h), and Rheal(2.94 ± 0.62 × 10−4cm2/h) at NP125were significantly ( P < 0.01) different from those at three other pressure conditions. In HaCaT cells, the Tmax(7.34 ± 0.29 h) and Rheal(6.82 ± 0.26 × 10−5cm2/h) at NP125were significantly ( P < 0.01) different from those at NP75. Prominent cell migration features were identified in cells at the specific negative pressure. Cell migration activities at different pressures can be documented with the real-time wound-healing measurement system. Negative pressure of 125 mmHg can help disassemble the cell junction to enhance epithelial migration and subsequently result in quick wound closure.