Low-Level Laser Therapy (780 nm) on VEGF Modulation at Partially Injured Achilles Tendon.

OBJECTIVE: The aim of this study was to analyze the modulatory effects of near infrared (780 nm) low-level laser therapy (LLLT) on the presence of the vascular endothelial growth factor (VEGF) in the partially injured Achilles tendons of rats.

BACKGROUND: LLLT stimulates the healing process for Achilles tendon injuries, although the extent of the modulatory effect of LLLT on the VEGF levels found in the injured tendons remains unclear.

METHODS: Sixty-five male Wistar rats were distributed in the following seven groups: LASER 1, 3, and 7 (10 partially injured Achilles tendons in each group, which were treated with LLLT for 1, 3, and 7 days, respectively); Sham 1, 3, and 7 (same injury, with simulated LLLT); Control group containing the five remaining animals and in which no procedures were performed. LLLT was applied once a day for 10 sec, with a mean power of 70 mW and fluency of 17.5 J/cm(2). After euthanasia, all of the Achilles tendons were surgically removed and the VEGF levels were analyzed using immunohistochemistry.

RESULTS: The VEGF levels remained close to normal (p > 0.05) when comparing the experimental groups (LASER and Sham: 1, 3, and 7) with the Control group.

CONCLUSION: LLLT did not stimulate the expression of VEGF in the treated Achilles tendons.