Effects of Narrow-band IR-A and of Water-Filtered Infrared A on Fibroblasts.

Exposures of the skin with electromagnetic radiation of wavelengths between 670 nm and 1400 nm are often used as a general treatment to improve wound healing and reduce pain, for example, in chronic diabetic skin lesions. We investigated the effects of water-filtered infrared A (wIRA) and of narrow-band IR-A provided by a light-emitting diode LED (LED-IR-A) irradiation in vitro on 3T3 fibroblast cultures under defined conditions with and without glyoxal administration. Glyoxal triggers the formation of advanced glycation end products, thereby mimicking a diabetic metabolic state. Cell viability and apoptotic changes were determined by flow cytometry after vital staining with Annexin V, YO-PRO-1 and propidium iodide (PI), and by SubG1 assay. Mitochondrial function and oxidative stress were examined by vital staining for radical production, mitochondrial membrane potential (MMP) and the ratio of reduced-to-oxidized glutathione (GSH/GSSG). The metabolic state was monitored by a resazurin conversion assay. The numbers of apoptotic cells were reduced in cultures irradiated with wIRA or LED-IR-A. More mitochondria showed a well-polarized MMP after wIRA irradiation in glyoxal damaged cells. LED-IR-A treatment specifically restored the GSH/GSSG ratio. The immediate positive effects of wIRA and LED-IR-A observed in living cells, particularly on mitochondria, reflect the therapeutic benefits of wIRA and LED-IR-A.

Effects of temperature and water-filtered infrared-A alone or in combination on healthy and glyoxal-stressed fibroblast cultures.

Water-filtered infrared-A (wIRA) radiation has been described as supportive for tissue regeneration. We sought to investigate in detail the wIRA effect at different temperatures in 3T3 fibroblasts that were treated with glyoxal to induce formation of advanced glycation end products (AGEs). Nonirradiated and nonglyoxal-treated cells served as controls. Experiments were carried out over a range of 37°-45°C with exact temperature monitoring to distinguish between temperature and wIRA effects. Metabolic activity was assessed by resazurin assay. Mitochondrial membrane potential was assessed by JC-1 vital staining. Apoptotic changes were determined by vital staining with annexin V and YO-PRO-1 and determination of subG1 DNA content. Temperature had a dominant effect overriding effects exerted by wIRA or glyoxal treatment. The number of apoptotic cells was significantly higher at 45°C, while the percentage of healthy cells was significantly lower at 45°C. WIRA irradiation itself or in combination with glyoxal treatment exerted no damaging effects on the fibroblasts at physiological (37°-40°C) or higher (42°-45°C) temperatures compared to untreated controls. Temperatures of 45°C, which can occur during inappropriate application of infrared irradiation, damage cells even in the absence of wIRA or glyoxal application.