Laser and LED phototherapies on angiogenesis

Angiogenesis is a key process for wound healing. There are few reports of LED phototherapy on angiogenesis, mainly in vivo. The aim of the present investigation was to evaluate histologically the angiogenesis on dorsal cutaneous wounds treated with laser (660 and 790 nm) or LEDs (700, 530, and 460 nm) in a rodent model. Twenty-four young adult male Wistar rats weighting between 200 and 250 g were used on the present study. Under general anesthesia, one excisional wound was created on the dorsum of each animal that were then randomly distributed into six groups with four animals each: G0—control; G1—laser λ660 nm (60 mW, ϕ ∼2 mm, 10 J/cm²); G2—laser λ790 nm (50 mW, ϕ ∼2 mm, 10 J/cm²); G3—LED λ700 ± 20 nm (15 mW, ϕ ∼16 mm, 10 J/cm²); G4—LED λ530 ± 20 nm (8 mW, ϕ ∼16 mm, 10 J/cm²); G5—LED λ460 ± 20 nm (22 mW, ϕ ∼16 mm, 10 J/cm²). Irradiation started immediately after surgery and was repeated every other day for 7 days. Animal death occurred at the eighth day after surgery. The specimens were removed, routinely processed to wax, cut and stained with HE. Angiogenesis was scored by blood vessel counting in the wounded area. Quantitative results showed that green LED (λ530 ± 20 nm), red LED (λ700 ± 20 nm), λ790 nm laser and λ660 nm laser caused significant increased angiogenesis when compared to the control group. It is concluded that both laser and LED light are capable of stimulating angiogenesis in vivo on cutaneous wounds and that coherence was not decisive on the outcome of the treatment.