Effects of LED phototherapy on relative wound contraction and reepithelialization during tissue repair in hypothyroid rats: morphometric and histological study

The aim of this study was to assess morphometrically and histologically, the effects of light-emitting diode (LED) (λ630 ± 20 nm) phototherapy on reepithelialization and wound contraction during tissue repair in hypothyroid rats. Thyroid hormone deficiency has been associated with disorders of tissue repair. LED phototherapy has been studied using several healing models, but their usefulness in the improvement of hypothyroidism wound healing remains unknown. Under general anesthesia, a standard surgical wound (1 cm2) was produced on the dorsum of 48 male Wistar rats divided into four groups of 12 animals each: EC—control euthyroid, ED—euthyroid + LED, HC—control hypothyroid, and HD—Hypothyroid + LED. The irradiation started immediately after surgery and was repeated every other day for 7 and 14 days. Photographs of the wound were taken at the day of the surgical procedure and on days 8 and 15 after surgery, when animals’ deaths occurred. The specimens were removed, routinely processed, and stained with hematoxylin/eosin. Seven days after the surgery, it was possible to observe statistically significant reductions in the wound area of the irradiated euthyroid group, in comparison to hypothyroid group, irradiated and non-irradiated (ANOVA, p < 0.05). The reepithelialization was significantly higher in the euthyroid and hypothyroid groups irradiated with LED than in the non-irradiated groups (Fisher’s test, p < 0.05). No significant difference was found in the experimental period of 14 days among the groups. The hypothyroidism delayed wound healing and the LED phototherapy, at these specific parameters, improved the process of reepithelialization in the presence of hypothyroidism.

[1]  Milene da Silva Melo,et al.  Comparison between wound healing in induced diabetic and nondiabetic rats after low-level laser therapy. , 2006, Photomedicine and laser surgery.

[2]  S. Reis,et al.  Influence of laser photobiomodulation upon connective tissue remodeling during wound healing. , 2008, Journal of photochemistry and photobiology. B, Biology.

[3]  Alyssa Panitch,et al.  Polymeric biomaterials for tissue and organ regeneration , 2001 .

[4]  J. Salisbury,et al.  A histomorphometric study of bone changes in thyroid dysfunction in rats. , 1995, Bone.

[5]  S. Reis,et al.  Phenotype characterization of pericytes during tissue repair following low‐level laser therapy , 2010, Photodermatology, photoimmunology & photomedicine.

[6]  Jie Li,et al.  Pathophysiology of acute wound healing. , 2007, Clinics in dermatology.

[7]  Adriana Clemente Mendonça,et al.  Mensuração de área de cicatrização por planimetria após aplicação do ultra-som de baixa intensidade em pele de rato , 2008 .

[8]  A. Pinheiro,et al.  Influence of laser (λ670 nm) and dexamethasone on the chronology of cutaneous repair. , 2010, Photomedicine and laser surgery.

[9]  M. Holick,et al.  A thyroid hormone deiodinase inhibitor can decrease cutaneous cell proliferation in vitro. , 2009, Thyroid : official journal of the American Thyroid Association.

[10]  D. Cambier,et al.  Increased fibroblast proliferation induced by light emitting diode and low power laser irradiation , 2003, Lasers in Medical Science.

[11]  F. Al-Watban.  Laser therapy converts diabetic wound healing to normal healing. , 2009, Photomedicine and Laser Surgery.

[12]  Noel T. Whelan,et al.  Effect of NASA light-emitting diode irradiation on wound healing. , 2001, Journal of clinical laser medicine & surgery.

[13]  Luciana Maria Pedreira Ramalho,et al.  Assessment of laser photobiomodulation and polarized light on the healing of cutaneous wounds on euthyroid and hypothyroid induced rats , 2010, BiOS.

[14]  Vanderlei Salvador Bagnato,et al.  Photobiomodulation on the angiogenesis of skin wounds in rats using different light sources. , 2007, Photomedicine and laser surgery.

[15]  G. I. Klebanov,et al.  Photobiological Principles of Therapeutic Applications of Laser Radiation , 2004, Biochemistry (Moscow).

[16]  E. Munin,et al.  Comparative analysis of coherent light action (laser) versus non-coherent light (light-emitting diode) for tissue repair in diabetic rats , 2009, Lasers in Medical Science.

[17]  Rodrigo Guerra de Oliveira,et al.  Modulação da proliferação fibroblástica e da resposta inflamatória pela terapia a laser de baixa intensidade no processo de reparo tecidual , 2006 .

[18]  P. Vestergaard.  Bone metabolism in type 2 diabetes and role of thiazolidinediones , 2009, Current opinion in endocrinology, diabetes, and obesity.

[19]  R. Nicolau,et al.  Tratamento de Hipersensibilidade Dentinária com Terapia com LED - Estudo Clínico Dentin Hypersensitivity Treatment Therapy With LED - Clinical Study , 2009 .

[20]  Rodrigo Guerra de Oliveira,et al.  Modulation of fibroblast proliferation and inflammatory response by low-intensity laser therapy in tissue repair process * Modulação da proliferação fibroblástica e da resposta inflamatória pela terapia a laser de baixa intensidade no , 2006 .

[21]  Prabhakar B. Angadi,et al.  Application of Lasers in Dentistry. , 2013 .

[22]  Rina Das,et al.  Effect of NASA light-emitting diode irradiation on molecular changes for wound healing in diabetic mice. , 2003, Journal of clinical laser medicine & surgery.

[23]  H. T. Whelan,et al.  Near-infrared light via light-emitting diode treatment is therapeutic against rotenone- and 1-methyl-4-phenylpyridinium ion-induced neurotoxicity , 2008, Neuroscience.

[24]  C. Baum,et al.  Normal Cutaneous Wound Healing , 2005 .

[25]  H. Ru,et al.  Materials Science & Engineering A , 2013 .

[26]  M. Holick,et al.  Thyroid hormone action on skin: diverging effects of topical versus intraperitoneal administration. , 2003, Thyroid : official journal of the American Thyroid Association.

[27]  K. Borsato,et al.  O processo de cicatrização influenciado pelo hipotireoidismo e pelo envelhecimento: estudo da cicatrização da parede abdominal, em ratos , 2005 .

[28]  L. Bonjardim,et al.  Immunohistochemical assessment of myofibroblasts and lymphoid cells during wound healing in rats subjected to laser photobiomodulation at 660 nm. , 2009, Photomedicine and laser surgery.

[29]  M. Holick,et al.  A role for thyroid hormone in wound healing through keratin gene expression. , 2004, Endocrinology.

[30]  Edmar Stieven Filho,et al.  Tracheal suture in rats with hypothyroidism: wound healing study. , 2009, Acta cirurgica brasileira.

[31]  A. Pinheiro.  Advances and perspectives on tissue repair and healing. , 2009, Photomedicine and laser surgery.

[32]  Rina Das,et al.  Clinical and experimental applications of NIR-LED photobiomodulation. , 2006, Photomedicine and laser surgery.

[33]  J. N. dos Santos,et al.  Effect of LED red and IR Photobiomodulation in tongue mast cells in Wistar rats: histological study. , 2011, Photomedicine and laser surgery.