| PHOTOTHERAPY | ARTICLE whom found the end result satisfactory.


Treatment of stretch marks on dark skin The treatment protocol for dark skin differs only in the dose of irradiation (power x time) of the LED therapy, which can be raised up to 16 J/cm2


The final treatment results of all skin types were identical.


Description of expected effects with the technologies used LED photobiomodulation The light emitted by an LED is a cold light, monochromatic, incoherent. Unlike lasers, LEDs do not supply enough power to damage tissue, but do provide enough energy to stimulate a cellular response of the body to induce healing. The light is a wave composed of multiple wavelengths


and characterised by a specific colour. Visible waves are referred to as ÔcoloursÕ, while others are invisible, such as UV and infrared. Each wave produces a specific electromagnetic vibration. Thus, the light colours range from red (620–680 nm) to violet (400 nm). Light is composed of particles called photons. Photobiomodulation with LED is a relatively new


but intrinsic


therapeutic approach to photoactivate the fibroblasts without thermal effect, in order to stimulate new collagen growth. This technique is based on principles of biology and physiology related to the laws of light and electromagnetic phenomena. Any molecule can be in different energy states. In the ground state a molecule has minimum energy. Absorption of light will bring it to higher energy levels27–32


.


The effect of photobiostimulation by a low intensity, cold, red light was discovered in 196833


, and was


afterwards confirmed in the 1980s by Professor Tiina Karu34


. Karu showed that cell cultures grew from 300 to


600 times faster when exposed to that type of light. In 2001, an American professor of paediatric neurology, Dr Harry Whelan, confirmed this thesis35


.


The irradiation by photons of light of a specific and controlled wavelength, emitted by LED, is absorbed


if the skin is very dark.


through the skin and connective tissue, and stimulates photoreceptors or cellular substrates, causing a chain of biochemical reactions that can include biological changes. These biological changes can be defined as the result of a process called ÔphotobiomodulationÕ . A number of studies have demonstrated that


irradiation with red LED light increases the mitochondrial membrane potential of cells, which, simply put, increases the adenosine diphosphate (ADP)Ð adenosine-5-triphosphate (ATP) exchange ratio, as well as ribonucleic acid (RNA). The action in mitochondria is primarily linked to two photoreceptors: the intermediate form of cytochrome c oxidase and nicotinamide adenine dinucleotide (NADH) dehydrogenase. Cytochrome c oxidase is the terminal enzyme


Photobiomodulation


with LED is a relatively new but intrinsic


therapeutic approach to photoactivate the fibroblasts without


of the respiratory chain that enables the transfer of electrons from cytochrome c to oxygen molecules. Cytochrome c plays a key role in the bioenergetics of the cell in particular, in fibroblasts, endothelial vessels, the lymphatic system, and osteoblasts36, 37


. The activation of electron


thermal effect, in order to stimulate new collagen growth.


flow in the respiratory chain activates the production of superoxide anions, which stimulate the synthesis of ATP. Normally, the


mitochondria reabsorbs superoxide anions as a source of electrons for oxidative phosphorylation of ADP. Certain molecules, such as porphyrins, act as


reversible photosensitisers. The absorption of photons by these substances generates the oxygen singlet which causes changes in the redox system. Thus, the light wave stimulates changes and proliferation of fibroblast, collagen synthesis, growth factors and extracellular matrix production by mitochondrial oxygenation. Robert A. Weiss, MD, Associate Professor of Dermatology at Johns Hopkins University School of Medicine in


Figure 3 Patient three (A) before and (B) after treatment


prime-journal.com | March 2012


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