Red light-emitting diode on skin healing: an in vitro and in vivo experimental study

Tuany R Schmidt; Belkiss C Mármora; Fernanda T Brochado; Lucas Gonçalves; Paloma S Campos; Marcelo L Lamers; Aurigena A de Araújo; Caroline A C X de Medeiros; Susana B Ribeiro; Marco A T Martins; Emily F S Pilar; Manoela D Martins; Vivian P Wagner

doi:10.1016/j.abd.2024.02.008

Red light-emitting diode on skin healing: an in vitro and in vivo experimental study

An Bras Dermatol. 2024 Nov 8:S0365-0596(24)00201-0. doi: 10.1016/j.abd.2024.02.008. Online ahead of print.

Affiliations

¹ Department of Pathology, Faculty of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
² Department of Pathology, Faculty of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Department of Pediatric Dentistry, Orthodontics and Public Health, Faculty of Dentistry, Universidade de São Paulo, Bauru, SP, Brazil.
³ Post-Graduation Program Oral Science/Post-Graduation Program in Pharmaceutical Science, Department of Biophysics and Pharmacology, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.
⁴ Department of Biophysics and Pharmacology/ Postgraduate Program in Biological Science and Rede Nordeste de Biotecnologia, Universidade Federal do Rio Grande Norte, Natal, RN, Brazil.
⁵ Postgraduate Program in Biological Science and Rede Nordeste de Biotecnologia/Renorbio, Universidade Federal do Rio Grande Norte, Natal, RN, Brazil.
⁶ Department of Pathology, Faculty of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Department of Oral Medicine, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
⁷ Experimental Pathology Unit, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
⁸ Department of Pathology, Faculty of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Department of Oral Medicine, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Department of Oral Diagnosis, Faculty of Dentistry, Universidade de Campinas, Piracicaba, SP, Brazil.
⁹ Department of Oral Diagnosis, Faculty of Dentistry, Universidade de Campinas, Piracicaba, SP, Brazil; Oral Medicine Department, Faculty of Dentistry, Universidade de São Paulo São Paulo, SP, Brazil. Electronic address: vivianpwagner@usp.br.

PMID: 39521711
DOI: 10.1016/j.abd.2024.02.008

Abstract

Background: The clinical advantages of light-emitting diode (LED) therapy in skin healing and its underlying mechanism remain subjects of ongoing debate.

Objective: This study aims to explore the impact of LED therapy on normal skin keratinocytes (HaCaT) and in the repair of full-thickness dorsal wounds in Wistar rats.

Methods: HaCaT cell viability (SRB assay) and migration (scratch assay) were assessed under LED therapy, comparing stress conditions (2.5% FBS) with sham irradiation and optimal conditions (10% FBS). In vivo, 50 rats with induced wounds were divided into Sham and LED (daily treatment) groups. Euthanasia occurred at 3, 5, 10, 14, and 21 days for clinical, morphological, oxidative stress (MDA, SOD, and GSH), and cytokine analyses (IL-1β, IL-10, TNF-α).

Results: LED therapy significantly enhanced keratinocytes viability compared to sham irradiation, with minimal impact on cell migration. Clinical benefits were prominent on day 10, influencing inflammation progression and resolution on days 3 and 10. Re-epithelization remained unaffected. Reduced MDA and increased GSH levels were observed throughout, while SOD levels varied temporally. Notably, on day 10, LED significantly decreased IL-1β, IL-10, and TNF-α.

Study limitations: Although translational, clinical trial confirmation of observed benefits is warranted.

Conclusions: LED therapy expedites cutaneous healing in the experimental model, primarily modulating inflammation and enhancing antioxidant activity.

Keywords: Cell culture techniques; Cytokines; Dermatology; Low-level light therapy; Models, animal; Oxidative stress.