Non-thermal near-infrared exposure photobiomodulates cellular responses to ionizing radiation in human full thickness skin models

• Published in: Journal of photochemistry and photobiology. B, Biology Vol. 178; pp. 115 - 123
• Main Authors: König, Anke, Zöller, Nadja, Kippenberger, Stefan, Bernd, August, Kaufmann, Roland, Layer, Paul G., Heselich, Anja
• Format: Journal Article
• Language: English
• Published: Switzerland Elsevier B.V 01.01.2018; Elsevier BV
• Subjects: Apoptosis; Cancer; Cell proliferation; Cells; Cellular stress response; Deoxyribonucleic acid; DNA; DNA damage; DNA repair; Double-strand break repair; Exposure; Fibroblasts; I.R. radiation; In vitro full thickness skin model; Infrared radiation; Ionizing radiation; Irradiation; Keratinocytes; Medical treatment; Near infrared radiation; Near-infrared; Pain; Patients; Photobiomodulation; Pretreatment; Radiation effects; Radiation therapy; Skin; Stress response; Therapy; Wound healing; X-radiation; X-rays; In vitro full thickness skin model; X-radiation; Near-infrared; Photobiomodulation
• ISSN: 1011-1344; 1873-2682
• DOI: 10.1016/j.jphotobiol.2017.11.003

Ionizing and near-infrared radiation are both part of the therapeutic spectrum in cancer treatment. During cancer therapy ionizing radiation is typically used for non-invasive reduction of malignant tissue, while near-infrared photobiomodulation is utilized in palliative medical approaches, e.g. for pain reduction or impairment of wound healing. Furthermore, near-infrared is part of the solar wavelength spectrum. A combined exposure of these two irradiation qualities – either intentionally during medical treatment or unintentionally due to solar exposure – is therefore presumable for cancer patients. Several studies in different model organisms and cell cultures show a strong impact of near-infrared pretreatment on ionizing radiation-induced stress response. To investigate the risks of non-thermal near-infrared (NIR) pretreatment in patients, a human in vitro full thickness skin models (FTSM) was evaluated for radiation research. FTSM were pretreated with therapy-relevant doses of NIR followed by X-radiation, and then examined for DNA-double-strand break (DSB) repair, cell proliferation and apoptosis. Double-treated FTSM revealed a clear influence of NIR on X-radiation-induced stress responses in cells in their typical tissue environment. Furthermore, over a 24h time period, double-treated FTSM presented a significant persistence of DSBs, as compared to samples exclusively irradiated by X-rays. In addition, NIR pretreatment inhibited apoptosis induction of integrated fibroblasts, and counteracted the radiation-induced proliferation inhibition of basal keratinocytes. Our work suggests that cancer patients treated with X-rays should be prevented from uncontrolled NIR irradiation. On the other hand, controlled double-treatment could provide an alternative therapy approach, exposing the patient to less radiation. •Full thickness skin models (FTSM) are usable skin equivalents for radiation research.•Photobiomodulation by NIR effected several cellular processes in FTSM.•NIR pretreatment influences DNA-double strand break repair kinetics in FTSM.•NIR prevents X-ray induced decrease of BrdU-uptake but not reduction of Ki-67+ cells.•NIR influences X-ray induced apoptosis but not the morphology of FTSM.