Polarized light (λ400-2000 nm) on third-degree burns in diabetic rats: immunohistochemical study.
OBJECTIVE
The aim of this study was to evaluate with light microscopy the healing process of third-degree burns on diabetic rats treated with polarized light (λ400-2000 nm, 20 or 40 J/cm(2)/session, 40 mW/cm(2), 2.4 J/cm(2)/min, 5.5-cm beam diameter).


BACKGROUND
Uncontrolled diabetes mellitus causes severe disruption of the body's metabolism, including healing. Polarized light sources have been shown to be effective in improving healing in many situations.


METHODS
Diabetes mellitus was induced with streptozotocin (60 mg/kg) in 45 male Wistar albino rats, and a third-degree burn (1.5 by 1.5 cm) was created on the dorsum of each animal under general anesthesia. The animals were randomly distributed into three groups: control, 20 J/cm(2), and 40 J/cm(2). Each group was then divided into three subgroups based on time of death (7, 14, 21 d). Phototherapy (20 or 40 J/cm(2) per session) was carried out immediately after the burning and repeated daily until the day before death. Following animal death, specimens were removed, embedded in paraffin, sectioned, and stained with hematoxylin and eosin (HE) or Sirius Red or immunomarked with CK AE1/AE3 antibody. Qualitative and semiquantitative analyses were performed under light microscopy. The results were statistically analyzed.


RESULTS
The animals treated with 20 J/cm(2) showed significant differences with regard to revascularization and re-epithelialization. Although the 40 J/cm(2) group showed stimulation of fibroblastic proliferation as an isolated feature, no other difference from the control was observed.


CONCLUSIONS
Our results suggest that the use of polarized light at 20 J/cm(2) effectively improves the healing of third-degree burns on diabetic animals at both early and late stages of repair.
Center of Biophotonics, School of Dentistry, Federal University of Bahia, Salvador, BA, Brazil.
Priscila Chagas
PC
Oliveira
Antônio Luiz Barbosa
AL
Pinheiro
João Alves
JA
Reis Junior
Isabelle C V
IC
de Castro
Clarissa
C
Gurgel
Manuela Pimentel
MP
Noia
Gyselle C S
GC
Meireles
Maria Cristina
MC
Cangussu
Luciana Maria Pedreira
LM
Ramalho
D000818:Animals; D001707:Biopsy, Needle; D002056:Burns / Q000209:etiology / Q000473:pathology* / Q000628:therapy*; D003921:Diabetes Mellitus, Experimental / Q000150:complications*; D004195:Disease Models, Animal; D005347:Fibroblasts / Q000166:cytology; D007150:Immunohistochemistry; D015601:Injury Severity Score; D008297:Male; D018919:Neovascularization, Physiologic / Q000502:physiology; D010784:Photomicrography; D010789:Phototherapy / Q000379:methods*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D013311:Streptozocin; D014945:Wound Healing / Q000502:physiology*
D013311:Streptozocin