Photobiomodulation by helium neon and diode lasers in an excisional wound model: A single blinded trial

BACKGROUND: Application of different kinds of lasers in clinical and experimental studies causes photobiomodulation that works at localized cellular and humoral level on various biological systems. Increased numbers of fibroblasts, myofibroblast, and degranulation of mast cells have been the observed benefits post-irradiation. OBJECTIVE: Was to find out the effect of irradiation with energy densities of 3.38 J/cm(2), 8 J/cm(2), and 18 J/cm(2) on animal tissue (albino wistar rats) in an excisional wound model and to assess changes in biochemical (hydroxyproline) and histopathological levels in excisional wound model. MATERIALS AND METHODS: The animals were divided into 4 groups, which were labeled as L1, diode laser (18 J/cm(2)), L2 Helium-neon (He-Ne, 8 J/cm(2)), L3 diode laser (3.38 J/cm(2)), and sham treatment for control was depicted by C, respectively. Histological and hydroxyproline analysis was performed on 7, 14, 21 days of post-wounding. One-way analysis of variance, ANOVA and Bonferroni's multiple comparison tests were done for tissue hydroxyproline levels. RESULTS: There was no significant increase in the hydroxyproline content (P < 0.005) when observed in study group and compared to controls. Whereas significant epithelizations was seen in group treated with He-Ne laser of intensity of 8 J/cm(2). CONCLUSION: The experimental observations suggest that low intensity helium-neon laser of 8 J/cm(2) intensity facilitated photo stimulation by tissue repair, but failed to show significant tissue hydroxyproline levels in excisional wound model.