[Effects of low-level helium-neon laser on induced wound healing in rats].
OBJECTIVE
To evaluate the effects of low-level helium-neon (HeNe) laser on cutaneous wound healing in rats.


METHODS
Sixty Wistar rats were divided into control group and experimental group. A sutured longitudinal, dorsal-medial incision was made, with simple separate stitches. The experimental group was irradiated daily in three areas of the wound with HeNe laser (5mW maximum continuous power, 632.8 nm wavelength, 4 J/cm(2) energy density and 0.015 cm(2) laser beam area) for 36 seconds. The areas were evaluated on the third, seventh and fourteenth days postoperative. Histological sections were stained with hematoxylin-eosin to determine the type of inflammatory reaction according to the protocol by Vizzotto et al. (2003)* and with Picrosirius to identify types I and III collagen and the collagen maturation index (CMI). Immunohistochemical detection was employed with anti-CD45-LCA to recognize the inflammatory cells.


RESULTS
Both groups had the same inflammatory pattern. The experimental group had fewer inflammatory cells at the three evaluation times (p<0.001) with faster reduction in the number of leukocytes. The experimental group had greater total collagen density on the third day (p=0.001), with more type III collagen (p=0.001) and more type I collagen (p=0.001). There was no significant difference in the CMI.


CONCLUSIONS
Low-level laser irradiation does not change the quality of the inflammatory response, but it does reduce its intensity; it increases collagen deposition in the early stages of the healing process and does not interfere with collagen maturation.
Busnardo
Viviane L
VL
Pontifícia Universidade Católica do Paraná, Curitiba, PR, Brasil. vivianelucci@up.edu.br
Biondo-Simões
Maria L P
ML
D000818:Animals; D054020:Lasers, Gas / Q000627:therapeutic use*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000293:injuries*; D014945:Wound Healing