Abstract
Purpose :
The limited options available for the treatment of eye infections and the increasing resistance of bacteria to antibiotics emphasize the urge to find new therapeutic possibilities. The disinfective potential of cold plasma therapy, due to the induction of reactive oxygen and nitrogen species (ROS, RNS), makes this approach a considerable possibility in the treatment of eye infections. However, to ensure effective and safe application, optimal conditions need to be found. In this study, we show the effects of cold plasma treatment using kINPen MED (neoplas tools GmbH) on cultured primary ocular cells.
Methods :
The effect of cold plasma was tested on primary human corneal limbal epithelial cells (pHCLEC) and human corneal endothelial cells (HCEC-12). Cells were exposed to cold plasma for 0.5, 1, 2, 5 and 10 min, with a distance of 5 cm and 90° angle of incidence under constant moisturization. Metabolic activity as measure for cell viability was analyzed by Cell Counting Kit - 8 (CCK-8) at 4 and 24 hours after treatment. Cell morphology and density were examined by phase contrast microscopy. In addition, the effects of cold plasma treatment on oxidative stress and apoptosis induction were investigated by Western blot.
Results :
Four hours after treatment 89.5% (0.5 min), 72.6% (1 min) 18.3% (2 min), 13.8% (5 min) and 15.6% (10 min) of the initial metabolic activity could be measured in HCEC-12. Within 24 h, cells treated for 0.5, 1 and 2 min have recovered to 131.4%, 112.7% and 64.4%, respectively. In these samples no changes in morphology or in cell density could be noticed directly after treatment. After further 24 hours cell density visibly increased.
Western blot analysis did not show evident difference in GPX-1 levels between different exposure times as well as in comparison to negative control, in both cell types. Slight PARP cleavage could be detected in all treated HCEC-12 samples, while in pHCLEC this was not the case.
Conclusions :
In our study we could show that argon cold plasma treatment with kINPen MED device for 0.5 – 2 min caused no effects on the viability of ocular cells and does not trigger apoptosis or induce oxidative stress in primary HCLEC. These findings support the hypothesis, that in an optimized setting, high disinfective power of cold plasma can be delivered while ensuring safety for the surrounding ocular tissue.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.