Original Article

The effect of low-level laser therapy and stress on wound healing in rats


Background: Many studies have been performed on the effect of low level laser on wound healing which has been associated with different and sometimes contradictory results. On the other hand, considering that stress may affect the immune system the fact that it may delay wound healing has also been addressed. Therefore, the present study aimed to investigate the simultaneous effect of low level laser therapy and stress on wound healing at the three levels of histology (histological changes), biomechanics (stress and strain assessment) and macroscopic (wound size). Materials and Methods: In this interventional study, 72 male Wistar rats (8-10 weeks old, weight range: 240 to 330g) were randomly divided into three treatment groups and one control group. (18 per group). In all the rats, a 2.5cm full-thickness skin incision was made on the dorsal spine. Intervention was performed from day 1 to day 21 every other day with Kals-DX61 laser (cap s) with wavelength: 660nm, dose 3J/cm2, 100 sec and power density 30mW/cm2. Then, wound size was measured weekly until the third week (day 21). Then, tension metric tests were performed to evaluate the stress and strain of the restored tissue. At the end of each week, three animals from each group were sacrificed for histopathological evaluation. Results: There was a significant difference between the stress/no laser and laser/no stress groupsin all stages of evaluation. Mean and standard deviation of stress and strain were not significantlydifferent in the study groups. Conclusion: Stress can potentially slow the wound healing process, while receiving low level laser therapy speeds up the wound healing process, although in the end there was no significant difference in biomechanical characteristics between the groups. Keywords: Low level laser therapy; Rat; Stress; Wound healing.
1. Pugliese LS, Medrado AP, Reis SRdA, Andrade ZdA. The influence of low-level laser therapy on biomodulation of collagen and elastic fibers. Pesqui Odontol Bras. 2003;17(4):307-13.
2. Alexandratou E, Yova D, Handris P, Kletsas D, Loukas S. Human fibroblast alterations induced by low power laser irradiation at the single cell level using confocal microscopy. Photoch Photobio Sci. 2002;1(8):547-52.
3. Gul NY, Topal A, Cangul IT, Yanik K. The effects of topical tripeptide copper complex and helium‐neon laser on wound healing in rabbits. Vet Dermatol. 2008;19(1):7-14.
4. Demidova‐Rice TN, Salomatina EV, Yaroslavsky AN, Herman IM, Hamblin MR. Low‐level light stimulates excisional wound healing in mice. Lasers Surg Med. 2007;39(9):706-15.
5. Papillion P, Valiulis J, Cunningham M, Simolke E, Veillon D, Mukherjee D, et al. The effect of 810 nanometer diode laser irradiation on healing of full-thickness skin wounds in rats. Wounds. 2004;16(12):355-8.
6. Hamblin MR, Demidova TN, editors. Mechanisms of low level light therapy. Mechanisms for low-light therapy; 2006: Int Soc Opt Photonics.
7. Salate AC, Barbosa G, Gaspar P, Koeke PU, Parizotto NA, Benze BG, et al. Effect of In-Ga-Al-P diode laser irradiation on angiogenesis in partial ruptures of Achilles tendon in rats. Photomed Laser Ther. 2005;23(5):470-5.
8. Jeong AS. Safety evaluation of low level light therapy on cancer cells 2016.
9. Carvalho PdTCd, Mazzer N, Reis FAd, Belchior ACG, Silva IS. Analysis of the influence of low-power HeNe laser on the healing of skin wounds in diabetic and non-diabetic rats. Acta Cir Bras. 2006;21(3):177-83.
10. Demir H, Balay H, Kirnap M. A comparative study of the effects of electrical stimulation and laser treatment on experimental wound healing in rats. J Rehabil Res Dev. 2004;41(2).
11. Yasukawa A, HRUI H, Koyama Y, Nagai M, Takakuda K. The effect of low reactive-level laser therapy (LLLT) with helium-neon laser on operative wound healing in a rat model. J Vet Med Sci. 2007;69(8):799-806.
12. Kesava Reddy G. Comparison of the photostimulatory effects of visible He‐Ne and infrared Ga‐As lasers on healing impaired diabetic rat wounds. Lasers Surg Med. 2003;33(5):344-51.
13. Rocha Júnior AM, Vieira BJ, Andrade LCFd, Aarestrup FM. Effects of low-level laser therapy on the progress of wound healing in humans: the contribution of in vitro and in vivo experimental studies. J Vasc Bras. 2007;6(3):257-65.
14. Hopkins JT, McLoda TA, Seegmiller JG, Baxter GD. Low-level laser therapy facilitates superficial wound healing in humans: a triple-blind, sham-controlled study. J Athl Train. 2004;39(3):223.
15. SIMUNOVIC Z, IVANKOVICH AD, DEPOLO A. Wound healing of animal and human body sport and traffic accident injuries using low-level laser therapy treatment: a randomized clinical study of seventy-four patients with control group. J Clin Laser Med Surg. 2000;18(2):67-73.
16. Al-Watban F, Bernard L. Therapeutic photons in wound healing. Global healthcare. 2002:1-10.
17. Crowther M, Brown N, Bishop E, Lewis C. Microenvironmental influence on macrophage regulation of angiogenesis in wounds and malignant tumors. J Leukoc Biol. 2001;70(4):478-90.
18. Kiecolt-Glaser JK, McGuire L, Robles TF, Glaser R. Psychoneuroimmunology and psychosomatic medicine: back to the future. Psychosom Med. 2002;64(1):15-28.
19. Zabrodsky PF. The Mechanisms of Formation of Immunodeficiency’s, Autoimmune Reactions and Hypersensitivity under the Influence of Xenobiotics. J Immuno Allerg. 2019;1(1):1-5.
20. Bartanusz V, Aubry J-M, Jezova D, Baffi J, Kiss JZ. Up-regulation of vasopressin mRNA in paraventricular hypophysiotrophic neurons after acute immobilization stress. J Neuroendocrinol. 1993;58(6):625-9.
21. Mester E, Korenyi-Both A, Spiry T, Tisza S. The effect of laser irradiation on the regeneration of muscle fibers (preliminary report). Z Exp Chir. 1975;8(4):258-62.
22. Posten W, Wrone DA, Dover JS, Arndt KA, Silapunt S, Alam M. Low‐level laser therapy for wound healing: mechanism and efficacy. Dermatol Surg. 2005;31(3):334-40.
23. Anneroth G, Hall G, Ryden H, Zetterqvist L. The effect of low-energy infra-red laser radiation on wound healing in rats. Brit J Oral Max Surg. 1988;26(1):12-7.
24. Eming SA, Martin P, Tomic-Canic M. Wound repair and regeneration: mechanisms, signaling, and translation. Sci Transl Med. 2014;6(265):265sr6-sr6.
25. Denda M, Tsuchiya T, Elias PM, Feingold KR. Stress alters cutaneous permeability barrier homeostasis. Am J Physiol Regul Integr Comp Physiol. 2000;278(2):R367-R72.
26. Padgett DA, Glaser R. How stress influences the immune response. Trends immunol. 2003;24(8):444-8.
27. ZOELLER RT, KABEER N, ALBERS HE. Cold exposure elevates cellular levels of messenger ribonucleic acid encoding thyrotropin-releasing hormone in paraventricular nucleus despite elevated levels of thyroid hormones. Endocrinology. 1990;127(6):2955-62.
28. Fatehi M, Anvari K, Fatehi-Hassanabad Z. The beneficial effects of protein tyrosine kinase inhibition on the circulatory failure induced by endotoxin in the rat. Shock. 2002;18(5):450-5.
29. Miller AH. Neuroendocrine and immune system interactions in stress and depression. Psychiatr Clin North Am. 1998;21(2):443-63.
30. Hawkins D, Abrahamse H. Laboratory methods for evaluating the effect of low level laser therapy (LLLT) in wound healing. Afr J Biomed Res. 2005;8(1):1-14.
31. Enwemeka CS. Attenuation and penetration of visible 632.8 nm and invisible infra-red 904nm light in soft tissues. Laser Ther. 2000;13(1):95-101.
IssueVol 7, No 4 (Autumn 2020) QRcode
SectionOriginal Article(s)
DOI https://doi.org/10.18502/jcr.v7i4.5554
Low level laser therapy; Rat; Stress; Wound healing.

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How to Cite
Dalband M, Azizi S, Karimzadeh M, Asnaashari M, Farhadinasb A, Azizi M, Ramezani M. The effect of low-level laser therapy and stress on wound healing in rats. J Craniomaxillofac Res. 7(4):186-194.