title: Effect of LED phototherapy (λ700 ± 20 nm) on TGF-β expression during wound healing: an immunohistochemical study in a rodent model.
abstract: OBJECTIVE
  The aim of the present investigation was to evaluate transforming growth factor β (TGF-β) expression on cutaneous wounds in rodents treated or not treated with LED light.
  
  
  BACKGROUND
  TGF-β is a multifunctional cytokine that presents a central action during tissue repair. Although several studies both in vitro and in vivo have shown that LED phototherapy influences tissue repair, a full understanding of the mechanisms involved in its usage, such as in the modulation of some growth factors, remains unclear.
  
  
  METHODS
  Under general anesthesia, 24 young adult male Wistar rats weighing 200-250 g had one excisional wound created on the dorsum of each, and were randomly distributed into two groups: G0 (Control) and G1 (LED, λ700 ± 20 nm, 16 mW, SAEF = 5 J/cm(2), Illuminated Area = 2 cm(2), 8 mWcm(2), 626 s) Each group was subdivided into three subgroups according to the animal death timing (2, 4, and 6 days). LED phototherapy started immediately after surgery and was repeated every other day during the experimental time. Following animal death, specimens were removed, routinely processed to wax, cut and immunomarked with polyclonal anti-TGF-β, and underwent histological analysis by light microscopy. The mean area of expression of each group was calculated. The data were statistically analyzed using ANOVA and Tukey's test.
  
  
  RESULTS
  The area of the expression of TGF-β on LED-irradiated animals was significantly smaller than on controls at day 2 (p = 0.013). No significant difference was found at later times. It is concluded that the use of LED light, at these specific parameters, caused an inhibition of the expression of TGF-β at an early stage of the healing process.
authors: Center of Biophotonics, School of Dentistry, Federal University of Bahia, Salvador, Bahia, Brazil.
authors: Ana Paula Cavalcanti
authors: AP
authors: de Sousa
authors: Alberto de Aguiar Pires
authors: Ade A
authors: de Aguiar Valença Neto
authors: Antônio Márcio Teixeira
authors: AM
authors: Marchionni
authors: Marília
authors: M
authors: de Araújo Ramos
authors: João Alves
authors: JA
authors: dos Reis Júnior
authors: Manoela Carrera Martinez Cavalcante
authors: MC
authors: Pereira
authors: Maria Cristina Teixeira
authors: MC
authors: Cangussú
authors: Silvia Regina
authors: SR
authors: de Almeida Reis
authors: Antônio Luiz Barbosa
authors: AL
authors: Pinheiro