In vivo effects on the expression of vascular endothelial growth factor-A165 messenger ribonucleic acid of an infrared diode laser associated or not with a visible red diode laser

Abstract

Objective: This study investigated and correlated the kinetic expression of vascular endothelial growth factor (VEGF)-A(165) messenger ribonucleic acid (mRNA) with the associated use or not of an infrared laser and a visible red laser during the wound healing in rats.

Background data: There is a lack of scientific evidence demonstrating the influence of low-level laser therapy (LLLT) on the expression of VEGF mRNA in vivo.

Materials and methods: Forty-five Wistar rats were randomly allocated to one of three groups: I (n = 5, nonoperated animals), II (n = 25, operated animals), and III (n = 25, animals operated and subjected to laser irradiation). A surgical wound was performed using a scalpel in the right side of the tongue of operated animals. In group III, two sessions of laser irradiation were performed, one right after the surgical procedure (infrared laser, 780 nm, 70 mW, 35 J/cm(2)) and the other 48 h later (visible red laser, 660 nm, 40 mW, 5 J/cm(2)). Five animals each were sacrificed 1, 3, 5, and 7 days postoperatively in groups II and III, and samples of tongue tissue were obtained. The animals of group I were sacrificed on day 7. Total RNA was extracted using guanidine-isothiocyanate-phenol-chloroform method. The results of horizontal electrophoresis after reverse transcription polymerase chain reaction permitted the ratio of VEGF-A(165) mRNA and glyceraldehyde 3-phosphate dehydrogenase mRNA expression for groups I, II, and III to be assessed (two-way analysis of variance and Tukey test, p < 0.05).

Results: The expression of VEGF-A(165) mRNA in group II (0.770 +/- 0.098) was statistically greater than that observed in groups I (0.523 +/- 0.164) and III (0.504 +/- 0.069) in the first day after surgery (p < 0.05). Significant differences between the groups were not observed in other time periods.

Conclusion: LLLT influenced the expression of VEGF-A(165) mRNA during wound healing after a surgical procedure on the tongue of Wistar rats.