Dose and wavelength of laser light have influence on the repair of cutaneous wounds

The objective of the present study was to compare histologically the effect of GaAlAs (lambda830 nm, phisimilar to2 mm(2), 35 mW) and InGaAIP (lambda685 nm, phisimilar to2 mm(2), 35 mW) lasers, alone or in association with doses of 20 or 50 J/cm(2) on cutaneous wounds in the dorsum of the Wistar rat. Background Data: The healing time of surgical wounds is of extreme importance and it is usually associated with a post-operative period free of infection and with less pain and inflammation. Materials and Methods: Sixty Wistar rats were divided into seven groups: Group I-control (non-irradiated); Group II-lambda685 nm, 20 J/cm(2); Group III-lambda830 Inn, 20 J/cm(2); Group IV-lambda685 mu and lambda830 nm, 20 J/cm(2); Group V-lambda685 nm, 50 J/cm(2)); Group VI-lambda830 nm, 50 J/cm(2); and Group VII-lambda685 nm and 830 nm, 50 J/cm(2). The animals were sacrificed 3, 5, and 7 days after surgery. Results: Light microscopic analysis using H&E and Picrosirius stains showed that, at the end of the experimental period, irradiated subjects showed increased collagen production and organization when compared to non-irradiated controls. Inflammation was still present in all groups at this time. Conclusion: Group IV (lambda830 nm and lambda685 nm, 20 J/cm(2)) presented better results at the end of the experimental period. It is concluded that low-level light therapy (LLLT) can have a positive biomodulatory effect on the repair of cutaneous wounds.