Biomodulator effects of low level laser therapy on VEGF-A₁₆₅

Objectives: This study investigated and correlated the kinetic of expression of mRNA VEGF-A₁₆₅ with the use or not of visible red and/or infrared diode laser during the tissue repair in rats.

Methods: 55 Wistar rats were randomly assigned for groups: GI (n=5, not operated animals), GII (n=25, operated animals) and GIII (n=25, operated and irradiated animals). A surgical wound was performed by scalpel in the right side of the tongues of operated animals. Two sessions of laser irradiation were accomplished, the first one right after the surgical procedure (infrared laser, 780 nm, 70 mW, 35 J/cm²) and the second one, 48 h after of the beginning of the experiment (visible red laser, 660 nm, 40 mW, 5 J/cm²), in the group GIII. 5 animals were sacrificed in both of groups GII and GIII on days 1, 3, 5 and 7 and samples of tongue tissue were obtained. The animals of group GI were sacrificed on day 7. The total RNA was extracted by using of guanidine-isotiocianate-phenol-chloroform method. The results of horizontal electrophoresis after RT-PCR permitted to assess the ratio of mRNA GAPDH and VEGF-A₁₆₅ expression for groups GI, GII and GIII (two-way ANOVA, Tukey's test, p<0.05). The animals were weighted to control their growth standards. Results: The expression of mRNA VEGF-A₁₆₅ in the group GII (0.770 ± 0.098) was statistically greater than that observed in the groups GI (0.523 ± 0.164, p=0.0285) and GIII (0.504 ± 0.069, p=0.0101) in the first day. Significant differences among the groups GI, GII and GIII were not observed in other time periods.

Conclusions: Therefore, infrared diode laser was able to modulate the expression of mRNA VEGF-A₁₆₅ during the first day of tissue repair process of wounds in rat tongues.

This research was supported by CNPq – Brazil.