Skin Tissue Healing Induced by Coherent (Laser) or Non-Coherent (LED) Light Therapy on Aged Rats

Abstract

Objectives: The purpose of this study was to evaluate the effect of low level laser therapy compared to light emitting diode (LED) therapy on the process of skin healing in aged rats.Background data: Studies demonstrated the effectiveness of therapy with coherent light in the visible spectrum to optimize the process of tissue repair, and some studies suggests that comparable effectiveness could be reached with the lower costs noncoherent light in the same spectral region. Materials and methods:We used 54 elderly male albino Wistar rats (14 months old) which were submitted to surgical lesions in the dorsum, with a punch of 0.8 cm diameter. The animals were separated into: three groups were selected as controls, three groups were treated with laser (660 nm, 30 mW) and three groups were treated with LED (640 nm, 40 nm bandwidth, 54 mW). The lesions of the control group did not receive any light therapy. The lesion's treatments in the laser and LED groups were initiated 30 min. after injury with fluence of 6 J/cm 2 and repeated every 48 h in three application's sessions. Animals were sacrificed at the 144, 312 and 480 h postsurgery. Histomorphological and histomorphometrical parameters were quantified in the lesioned areas.Results: showed an increase in the number of inflammatory cells, blood vessels, fibroblasts and collagen in all treated groups, demonstrating that the laser and LED improved the quality of the heal in the elderly animals. Conclusion:The LED therapy promoted better healing quality than laser.