Proliferation-Related Activity in Endothelial Cells Is Enhanced by Micropower Plasma

Abstract

Nonthermal plasma has received a lot of attention as a medical treatment technique in recent years. It can easily create various reactive chemical species (ROS) and is harmless to living body. Although plasma at gas-liquid interface has a potential for a biomedical application, the interactions between the gas-liquid plasma and living cells remain unclear. Here, we show characteristics of a micropower plasma with 0.018 W of the power input, generated at gas-liquid interface. We also provide the evidence of plasma-induced enhancement in proliferation activity of endothelial cells. The plasma produced H2O2, HNO2, and HNO3 in phosphate buffered saline containing Mg++ and Ca++ (PBS(+)), and their concentration increased linearly during 600-second discharge. The value of pH in PBS(+) against the plasma discharge time was stable at about 7.0. Temperature in PBS(+) rose monotonically, and its rise was up to 0.8°C at the bottom of a cell-cultured dish by the plasma discharge for 600 s. Short-time treatment of the plasma enhanced proliferation activity of endothelial cells. In contrast, the treatment of H2O2 does not enhance the cell proliferation. Thus, the ROS production and the nuclear factor-kappa B (NF-κB) activation due to the plasma treatment might be related to enhancement of the cell proliferation. Our results may potentially provide the basis for developing the biomedical applications using the gas-liquid plasma.

Comparative Study between Direct and Indirect Treatment with Cold Atmospheric Plasma on In Vitro and In Vivo Models of Wound Healing

“…32 33,40 Interestingly, repeating indirect treatments (at 0 and 24 h after the scratch) using PAM for HaCaT (B), HMVEC (E), and 24 h after the scratch) using long-life species alone or together at a concentration corresponding treatment every 24 h did not increase mortality during a period of 72 h. This plasma source used higher power than was used in this study, and distance of source from cell viability was studied by Suzuki and Yoshino. 45 These investigators used micropower dielectric barrier discharge (DBD) as the power and a H 2 O 2 concentration that was similar to what were used in the current study: 0.018 W and 15 μ for treatment of 2 min (in our study, 0.09 W and 14 μ for 2 min). Suzuki and Yoshino found cells to be damaged after 5 min of treatment.…”

“…Susceptibility of endothelial cells to plasma was also shown by Arndt et al 33 The fact that plasma toxicity is time and power dependent was described 32,39,40,41 keratinocytes, [40][41][42]44 and endothelial cells. [33][34][35][36][37][38][39][40][41][42][43][44][45] However, the power of the plasma source was not always provided in previous publications, so it is not always possible to compare the cell-damage threshold in terms of produced energy and/or equivalent production of ROS. Kang et al…”

“…Suzuki and Yoshino found cells to be damaged after 5 min of treatment. 45 An ex vivo study performed by Hasse et al on human patient skin samples using kinPenMed (Neoplas GmbH, Greifswald, Germany), showed that the number of apoptotic cells increased with treatment time, and 44 Mortality that is induced by plasma is commonly associated with oxidative and liquids. 46 In fact, multiple studies have shown that plasma treatment induced increase in intracellular ROS concentration in treated cells, with the increase proportional to treatment time.…”

“…46 In fact, multiple studies have shown that plasma treatment induced increase in intracellular ROS concentration in treated cells, with the increase proportional to treatment time. 39,41,42,45 Kalghatgi et al reported that nonthermal DBD plasma generated ROS, such as superoxide anions, hydrogen peroxide, hydroxyl radicals, single oxygen, and ozone. 47 Cui et al reduced cell mortality after plasma treatment by adding Nacetylcysteine, an antioxidant and ROS scavenger molecule.…”

“…We checked to ensure that this concentration of H 2 O 2 added alone to the cell media (without plasma treatment) did not concentration was three times higher after plasma treatment than after H 2 O 2 was added to media. 45 This shows how mortality induced by plasmas can be triggered by ROS chemicals other than H 2 O 2 with a short half life, such as O 2 -, OH, or physical factors…”