RESUMEN
1. Lectins labeled with colloidal gold particles were used for the ultrastructural evaluation of the biological effects of GaAs softlaserirradiation on the healing of dog tendon wounds. 2. Six dogs were submitted to tenotomy and tenorrhaphy on the right and left hind legs. All animals received laser irradiation (4J/cm²) daily for ten days only on the left leg, and the right leg of the same animal was used as control. Biopsies were taken 11, 22 and 40 days after surgery. 3. Laser-irradiated and control tendon tissues were embedded in L.R. White resin and thin section were incubated in the presence of gold-labeled Arachis hypogaea (PNA), Canavalia ensiformes (Con A) and Triticum vulgare (WGA). 4. In general, the control and laser-irradiated tissues presented homogeneous and similar labelling of heterochromatin, rough endoplasmic reticulum and extracellular matrix. 5. We conclude that GaAs softlaser irradiation does not produce significant changes in the glycosylation of healing tendons