Laser Therapy, by Mary Dyson PHD FCSP continued page 4    For sale outside of the United States only!

HOW LLLT PRODUCES ITS EFFECTS continued

Cellular effects relevant to skin repair
The cellular effects of LLLT relevant to skin repair include the stimulation of
adenosine triphosphate (ATP) production
growth factor release by macrophages
keratinocyte proliferation
collagen synthesis
angiogenesis.

All of the above are required for skin to renew itself and repair the damage done to it by, for example, environmental factors such as excessive exposure to the elements, damage that accumulates with age.

Temporary vasodilatation following the exposure to red light improves the transport of essential nutrients and oxygen to the skin and the removal of toxic waste materials from it. It also gives sallow skin a radiant glow.

PAIN RELIEF BY LLLT
Although many of the reports of pain relief following exposure to LLLT are anecdotal, there have been a number of reports based on trials aimed at assessing LLLT as an antinociceptive or analgesic modality, one of the earliest being that of Walker 1983 who implicated alteration in serotonin metabolism as one mechanism of LLLT-mediated analgesia.

Rheumatoid pain
Walker et al (1987) reported a highly significant reduction (p<0.001) in the levels of pain and analgesic medication intake reported by rheumatic patients either treated with low intensity red laser or sham-irradiated, pain relief being greater in those given laser treatment. Palmgren et al (1989) found that treatment of the small joints of the hand in rheumatic patients with low intensity infrared laser was followed by reduced pain and swelling, reduced early morning stiffness and increased grip strength and range of movement. In contrast Basford et al (1987) found that red laser irradiation of the osteoarthritic thumbs of patients was not followed by significant reduction in pain; however, the power and energy levels used (0.9 mW and 0.081J) are well below those recommended for clinical application (Baxter 1994) and may have been sub threshold.

Chronic neurogenic pain
Moore et al (1988a) have investigated the effect of red laser in the treatment of patients with chronic neurogenic pain including that of post-herpetic neuralgia. It was found that there was a significant reduction in reported pain following treatment in comparison to that in sham-irradiated patients. Similar effects have been reported by Hong et al (1990) using the same equipment.

Mechanisms
It has been suggested by Obata et al (1990) that laser-mediated relief of rheumatic pain may be linked to autonomic changes that produce vasodilatation and slight increases in local temperature. It is also possible that laser treatment affects the synthesis, release and metabolism of a range of neurochemicals involved in nerve transmission and pain relief (Walker 1983). Relief following the stimulation of acupuncture points with LILT has been ascribed to the production of endogenous opiate-like peptides and serotonin by Zhong et al (1989).

CONCLUSIONS
Scarring associated with acne and skin deterioration due to ageing and sun damage can be alleviated by LLLT. These skin conditions involve tissue injury, the repair of which is improved by exposure to LLLT in the form of red light. LLLT can reduce the duration of inflammation, improving tissue repair where this is delayed or defective. It can also reduce both acute and chronic pain. By assisting in the resolution of inflammation, the proliferative phase of tissue repair begins earlier and the reparative process is completed earlier. Cell activity is jump-started by changes in membrane permeability. This occurs when the cells absorb red and/or infrared radiation. The cells are also energized when red light is absorbed by their mitochondria, stimulating the synthesis of ATP and thus providing readily available energy for cell activity. The improvement in the skin produced by LLLT has been described as skin rejuvenation (Lee 2002). The Beurer SoftLaserTM takes LLLT from the clinic into the home where it can be used regularly for skin care.

REFERENCES

Alam M, Dover JS 2003 Nonablative laser and light therapy: an approach to patient and device selection

Basford JR, Sheffield CG, Mair SD et al 1987 Low-energy helium-neon laser treatment of thumb osteoarthritis. Arch Phys Med Rehab 68:794-797 et al 1987

Baxter D 1994 Therapeutic lasers: theory and practice. Churchill Livingstone, Edinburgh.

Bjerring P, Clement M, Heickendorff L, Lybecker H, Kiernan M 2002 Dermal collagen production following irradiation by dye laser broadband light source. J Cosmet Laser Ther 4:39-43

Dyson M 2004 Adjuvant therapies: ultrasound, laser therapy, electrical stimulation, hyperbaric oxygen and negative pressure therapy. In: Chronic wound care: a problem-based learning approach. Eds: Morison MJ, Ovington LG, Wilkie K Mosby: Edinburgh, pp.129-159.

Dyson M, Young SR 1986 The effects of laser therapy on wound contraction and cellularity. Lasers Med Sci 1:125-130

El Sayed S, Dyson M 1990 Effect of laser pulse repetition rate and pulse duration on mast cell number and degranulation. Lasers Surg Med 19:433-437

Hirsch RJ, Shalita AR 2003 Lasers, light, and acne. Cutis 71:353-354

Hong JN, Kim TH, Lim SD 1990 Clinical trial of low-reactive laser therapy in 20 patients with post herpetic neuralgia. Laser Ther 2:167-170

Karu TI 1988 Molecular mechanisms of the therapeutic effect of low-intensity laser irradiation. Lasers Life Sci 2:53-74

Lee MW 2002 Combination visible and infrared lasers for skin rejuvenation. Semin Cutan Med Surg 21:288-300

Mester E, Mester AF, Mester A 1985 The biomedical effects of laser application. Lasers Surg Med 5:31-39

Moore KC, Hira N, Kumar PS et al 1988 A double blind crossover trial of low level laser therapy in the treatment of post herpetic neuralgia. Lasers Med Sci, Abstracts Issue, July 1988:301

Obata J, Yanase M, Honmura A, 1990 Evaluation of acute pain relief effects of serotonin in laser acupuncture analgesia. Am J Acupuncture 17:39-43
 
Palmgren N, Jensen GF, Kaae K et al 1989 Low-power laser in rheumatoid arthritis. Lasers Med Sci 4:193-196

Patel N, Clement M 2002 Selective nonablative treatment of acne scarring witH 585 nm flashlamp pulsed dye laser. Dermatol Surg 28:942-945

Tuner J, Hode L 2002 Laser Therapy: Clinical Practice and Scientific Background. Prima Books, Grangesberg, Sweden.

Walker JB 1983 Relief from chronic pain by low-power laser irradiation. Neurosci Lett 43:339-344

Walker JB, Akhanjee LK, Cooney MM et al 1987 Laser therapy for pain of rheumatoid arthritis. Clin J Pain 3:54-59

Young SR, Dyson M, Bolton P 1990 Effect of light on calcium uptake by macrophages. Laser Therapy 2:53-57

Young SR, Dyson M 1993 The effect of ultrasound and light therapy on tissue repair. In: Macleod DAD, Maughan C, Williams CR, Sharo JCM, Nutton R (eds) Intermittent high intensity exercise. Chapman and Hall, London, pp.321-328

Zhong X et al 1989 Correlation between endogenous opiate-like peptides and low-power laser therapy in rheumatoid arthritis by thermography. Laser Ther 2:28

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