Non-Coherent Near Infrared Radiation Protects Normal Human Dermal Fibroblasts from Solar Ultraviolet Toxicity

Abstract

The sun is the most important and universal source of non-ionizing radiation shed on human populations. Life evolved on Earth bathed by this radiation. Solar UV damages cells, leading to deleterious conditions such as photoaging and carcinogenesis in human skin. During the process of evolution, the cells selected dark- and light-dependent repair mechanisms as a defence against these hazardous effects. This study describes the induction by non-coherent infrared radiation (700-2000 nm), in the absence of rising temperature, of a strong cellular defense against solar UV cytotoxicity as well as induction of cell mitosis. Blocking mitoses with arabinoside-cytosine or protein synthesis with cycloheximide did not abolish the protection, leading to the conclusion that this protection is independent of cell division and of protein neosynthesis. The protection provided by infrared radiation against solar UV radiation is shown to be a long-lasting (at least 24 h) and cumulatif phenomenon. Infrared radiation does not protect the lipids in cellular membranes against UVA induced peroxidation. The protection is not mediated by heat shock proteins. Living organisms on the Earth's surface are bathed by infrared radiation every day, before being submitted to solar UV. Thus, we propose that this as yet undescribed natural process of cell protection against solar UV, acquired and preserved through evolutional selection, plays an important role in life maintenance. Understanding and controlling this mechanism could provide important keys to the prevention of solar UV damage of human skin.

Multiple roles of cytochrome c oxidase in mammalian cells under action of red and IR‐A radiation

“…If the UV radiation can have damaging effects upon human cells, and the redto-IR-A part of solar spectrum can have stimulating effects, then what could be the summary effects on the human skin? Menezes and coworkers (19) have suggested that preirradiation with IR light (e.g., during sunrise) is a natural process whereby cells are protected against the solar UV radiation, which was acquired and preserved through evolutional selection and plays an important role in life support. They found that visible-tonear-IR radiation at 400-2000 nm protected human dermal fibroblasts from UV-A and UV-B cytotoxity (19).…”

“…Menezes and coworkers (19) have suggested that preirradiation with IR light (e.g., during sunrise) is a natural process whereby cells are protected against the solar UV radiation, which was acquired and preserved through evolutional selection and plays an important role in life support. They found that visible-tonear-IR radiation at 400-2000 nm protected human dermal fibroblasts from UV-A and UV-B cytotoxity (19). It was also found in this work that the protection was independent of the (20).…”

Non-Thermal Effects of Near-Infrared Irradiation on Melanoma

“…The dermis tends to increase the amount of fluid by inducing an increase in collagen, elastin, and water-binding protein in order to protect subcutaneous tissues from NIR (Tanaka et al 2009a(Tanaka et al , 2009b. Pre-exposure of NIR prevents UV-induced toxicity (Danno K et al, 1992;Frank et al, 2004;Menezes et al, 1998), and this effect is independent of heat shock protein induction and cell division (Menezes et al, 1998). These findings suggest that NIR irradiation prepares skin to better resist the subsequent damage of UV or NIR.…”

LED photoprevention: Reduced MED response following multiple LED exposures

“…Overall, these results, although observed in a small sample of subjects, suggest that a state of cellular resistance to UV insults was induced following LED photoprophylaxis. It can be hypothesized that this cellular resistance may be achieved experimentally by triggering/stimulating an existing natural protection mechanism [3]. In effect, in the natural environment, visible and IR solar wavelengths predominate in the morning and UV-B and UV-A are predominant around noon.…”

“…In a study by Menezes et al [3], it was demonstrated that a narrow electromagnetic spectrum window IR wavelengths (700-2,000 nm) generated a strong cellular defense against solar UV cytotoxicity in the absence of rising skin temperature. In a follow-up to this study by Frank et al [4], it was proposed that IR irradiation prepares cells to resist UV-B-induced damage by affecting the mitochondrial apoptotic pathway.…”