Analysis of the influence of low-power HeNe laser on the healing of skin wounds in diabetic and non-diabetic rats.
OBJECTIVE
To study the influence of HeNe laser irradiation on the collagen percentage in surgically-induced skin wounds in rats with and without alloxan-induced diabetes, by morphometric analysis of collagen fibers.


METHODS
48 male Wistar rats were used, divided into groups: laser-treated diabetic (group 1); untreated diabetic (group 2); treated non-diabetic (group 3); and untreated non-diabetic (group 4). For groups 1 and 2, diabetes was induced by intravenous injection of alloxan (2,4,5,6-tetraoxypyrimidine; 5,6-dioxyuracil; Sigma), into the dorsal vein of the penis, at a rate of 0.1 ml of solution per 100 g of body weight. A wound was made on the back of all the animals. Groups 1 and 3 were treated with HeNe laser (4 J/cm2) for 60 s. One animal from each group was sacrificed on the 3rd, 7th and 14th days after wounding. Samples were taken, embedded in paraffin, stained with hematoxylin-eosin and Masson's trichrome, and morphometrically analyzed using the Imagelab software. The percentages of collagen fibers were determined from the samples from the euthanasia animals. The data were treated statistically using analysis of variance (ANOVA) and the Student t and Kruskal-Wallis tests. The significance level was set at 0.05 or 5%.


RESULTS
The results obtained from the samples taken on the third, seventh and fourteenth days after wounding demonstrated that the laser-treated group presented a statistically significant (p<0.05) greater mean quantity of collagen fibers than in the non-treated group, both for diabetic rats (p = 0.0104) and for non-diabetic rats (p = 0.039).


CONCLUSIONS
The low-power laser (632.8 nm) was shown to be capable of influencing the collagen percentage in skin wounds by increasing the mean quantity of collagen fibers, both for the diabetic and for the non-diabetic group.
Carvalho
Paulo de Tarso Camillo de
PT
Department of Physiotherapy, University for State and Pantanal Region Development, Campo Grande, MS, Brazil. ptpaulo@terra.com.br
Mazzer
Nilton
N
dos Reis
Filipe Abdalla
FA
Belchior
Ana Carulina Guimarães
AC
Silva
Iandara Schettert
IS
D000496:Alloxan; D000818:Animals; D003094:Collagen / Q000096:biosynthesis; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000503:physiopathology*; D028022:Low-Level Light Therapy; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000187:drug effects*; D018709:Statistics, Nonparametric; D014945:Wound Healing / Q000528:radiation effects*
D000496:Alloxan; D003094:Collagen