Macrophage responsiveness to light therapy

Abstract

Macrophages are a source of many important mediators of wound repair. It was the purpose of this study to see if light could stimulate the release of these mediators. In this study an established macrophage-like cell line (U-937) was used. The cells were exposed in culture to the following wavelengths of light: 660 nm, 820 nm, 870 nm, and 880 nm. The 820-nm source was coherent and polarised, and the others were non-coherent. Twelve hours after exposure the macrophage supernatant was removed and placed on 3T3 fibroblast cultures. Fibroblast proliferation was assessed over a 5-day period. The results showed that 660-nm, 820-nm, and 870-nm wavelengths encouraged the macrophages to release factors that stimulated fibroblast proliferation above the control levels, whereas the 880-nm wavelength either inhibited the release of these factors or encouraged the release of some inhibitory factors of fibroblast proliferation. These results suggest that light at certain wavelengths may be a useful therapeutic agent by providing a means of either stimulating or inhibiting fibroblast proliferation where necessary. At certain wavelengths coherence is not essential.

Blue and red light combination LED phototherapy for acne vulgaris in patients with skin phototype IV

“…The beneficial effects of red light on the skin have been suggested by many studies [35][36][37][38][39][40][41][42][43][44][45]. It has been demonstrated by an in vitro study that red light influenced cytokine release from macrophages, which consequently stimulated fibroblast proliferation [35].…”

“…It has been demonstrated by an in vitro study that red light influenced cytokine release from macrophages, which consequently stimulated fibroblast proliferation [35]. Karu [38,39] suggested that absorption of red and near-infrared light by photoacceptor molecules within the respiratory chains can cause alteration in the redox status of the cells and activate the nucleic acid synthesis to accelerate cell proliferation.…”

The use of low-level light therapy in supportive care for patients with breast cancer: review of the literature

“…LLLT can also induce collagen synthesis and growth factor secretion. Furthermore, there is also a downregulation of the production of pro-inflammatory cytokines and cell apoptosis by LLLT [14][15][16][17][18][19][20].…”

Effects of GaAs laser and stretching on muscle contusion in rats

“…It has been demonstrated 8,9 that lasers operating at different wavelengths activate the macrophages to release factors that stimulate fibroblast proliferation. Low-intensity laser acts on the synthesis and collagen remodeling, fibroblast number, diameter, and tensile strength of the treated wounds 7 .…”