title: Evaluation of the effects of polarized light (λ400-200 nm) on the healing of third-degree burns in induced diabetic and nondiabetic rats.
abstract: OBJECTIVE
  The study evaluated, by light microscopy, the repair process on third-degree burns on diabetic and nondiabetic rats, illuminated or not, with a polarized light (PL) source.
  
  
  BACKGROUND
  Burns are severe injuries that result in the loss of fluid and destruction of tissue, infection, and shock that may result in death. Diabetes mellitus is a public health problem that, being uncontrolled, causes severe disturbance to the body metabolism, including on wound healing. PL sources have been shown to be effective in improving healing in many situations.
  
  
  METHODS
  Ninety male Wistar rats were divided into two groups (n=45): nondiabetic and diabetic. In one of the groups, diabetes mellitus was induced by streptozotocin. A third-degree burn, measuring 1.5×1.5 cm(2), was created in the dorsum of each animal. Phototherapy (λ400-2000 nm, 10.2 or 20.4 J/cm(2)) started immediately after burning and was repeated daily until animal death (7, 14, and 21 days). Specimens were taken, processed, and stained with H&E and Sirius red and immunomarked with cytokeratin (CK) AE1/AE3. Descriptive analysis was performed by light microscopy.
  
  
  RESULTS
  Animals subjected to phototherapy showed an acceleration of the repair, the dose of 10.2 J/cm(2) being the one that caused best results, including higher deposition of collagen, quicker inflammatory reaction, and improved revascularization.
  
  
  CONCLUSIONS
  Our results suggest that the use of PL (10.2 J/cm(2)) improves the healing of third-degree burns on both diabetic and nondiabetic animals.
authors.affiliation: Center of Biophotonics, School of Dentistry, Federal University of Bahia, Salvador, Bahia, Brazil.
authors.forename: Priscila Chagas
authors.initials: PC
authors.lastname: Oliveira
authors.forename: Antônio Luiz Barbosa
authors.initials: AL
authors.lastname: Pinheiro
authors.forename: Isabele C V
authors.initials: IC
authors.lastname: de Castro
authors.forename: João Alves
authors.initials: JA
authors.lastname: Reis
authors.forename: Manuela Pimentel
authors.initials: MP
authors.lastname: Noia
authors.forename: Clarissa
authors.initials: C
authors.lastname: Gurgel
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Teixeira Cangussú
authors.forename: Luciana Maria
authors.initials: LM
authors.lastname: Pedreira Ramalho
mesh_terms: D000818:Animals; D002056:Burns / Q000473:pathology / Q000628:therapy*; D003921:Diabetes Mellitus, Experimental / Q000150:complications* / Q000473:pathology; D004195:Disease Models, Animal; D008297:Male; D010789:Phototherapy; D051381:Rats; D017208:Rats, Wistar; D014945:Wound Healing / Q000528:radiation effects*