Quantifying cell behaviors in negative-pressure induced monolayer cell movement

BACKGROUND: Negative-pressure of 125 mmHg (NP) has been shown to accelerate wound healing. Effects of NP on human keratinocyte behaviors during wound healing process were highlighted in this study. METHODS: An NP incubator incorporating the electric cell–substrate impedance sensing (ECIS) technique has been built to quantify monolayer keratinocytes movement in serum-free media at the ambient pressure (AP) and NP for 12 h. Monolayer cell motions were continuously recorded by ECIS in the frequency range of 22.5–64 kHz. Membrane capacitance (C(m)), cell–substratum resistance (α), and cell–cell junction resistance (R(b)) were evaluated in cells at the different pressures. RESULTS: A greater monolayer cell migration distance was found in cells at NP. Decreased cell–substratum adhesion reflected in the significantly low α (AP:NP = ∼5 Ω(0.5):∼3 Ω(0.5)⋅cm), decreased integrin expression, and increased cell–substratum distance were seen in cells at NP. A significantly increased C(m) (AP:NP = ∼4:∼8 μF/cm(2)) in association with increased membrane ruffling and microtubule filaments were observed early in the monolayer cell movement at NP. A progressive drop in the R(b) from 1.2 Ω·cm(2) to 0.8 Ω·cm(2) corresponding to the gradually decreased E-cadherin expressions were observed 6 h after wound closure after NP treatment. CONCLUSION: A quick membrane ruffling formation, an early cell–substratum separation, and an ensuing decrease in the cellular interaction occur in cells at NP. These specific monolayer cell behaviors at NP have been quantified and possibly accelerate wound healing.