Analysis of the influence of low-power HeNe laser on the healing of skin wounds in diabetic and non-diabetic rats

Abstract

Purpose: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 (2,4,5,5, 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/cm 2 ) for 60 s. One animal from each group was sacrificed on the 3 rd , 7 th and 14 th 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). Conclusion: 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. Key words: Laser Therapy, Low-Level. Wound Healing. Collagen. Rats. RESUMOObjetivo: Estudar, comparativamente, através de análises morfométricas das fibras colágenas, a influência da irradiação com laser HeNe no percentual de colágeno de lesões cutâneas induzidas em ratos diabéticos aloxânico e não diabéticos. Métodos: Foram utilizados 48 ratos Wistar, machos sendo estes divididos em grupos: Grupo 1 diabético tratado com laser, Grupo 2 diabético não-tratado, Grupo 3 não-diabético tratado e Grupo 4 não-diabéticos não-tratados. Nos grupos 1 e 2 diabetes foi induzido por injeção intravenosa (veia dorsal do pênis de Aloxana (2, 4, 5, 6 -Tetraoxypyrimidina; 5 -6 Dioxyuracila) SIGMA, 0.1ml de solução a cada 100 g. de peso corporal. Todos os animais foram submetidos a uma lesão no dorso e os Grupos 1 e 3, foram tratados com laser HeNe com dosagem de 4 J/cm 2 por 36 s. Um animal de cada grupo sofreu eutanásia no 3º, 7º e 14 dias após a lesão e retiradas as amostras que foram emblocadas em parafina, coradas com H.E., Tricrômico de Masson e a analisadas morfométricamente pelo software IMAGELAB . Os dados resultantes foram tratados estatisticamente pela análise de variância (ANOVA), e pelos testes t e Kruskal-Wallis fixou-se em 0,05 ou 5% (a £ 0,05) o nível ...

Effect of low level laser on sutured wound healing in rats

“…However, the blood vessels content in 8 days was significantly reduced in both irradiated and nonirradiated groups when compared to 15 days. Similar findings were reported in previous investigations 11 , so that it is suggested a close relationship between the evolution of the scarring events and progressive reduction of neovascularization during the healing process.…”

“…On the other hand, in the later stages of the repair process the fibers exhibit an organizational pattern more compact, thicker bundles of red-orange color, indicating a type I collagen 2,11,19 .…”

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