RESUMEN
INTRODUCTION: Low-intensity laser (LILT) and LED therapy are indicated in repairing surgical incisions, which occur in cardiac surgery. One major concern in this case is the presence of metallic wire used for sternal sutures, its temperature may rise while using a laser or LED. This study aimed to analyze the tensiometric properties of the skin tissue with longitudinal incision and metallic wire implant used for sternal suture irradiated with LILT and LED. METHODS: Twenty-five subjects (Rattus norvegicus) were submitted to thoracic incision with implantation of metallic wire, and subsequently divided into five groups: GI (control group); GII (laser group 6J/cm²); GIII (laser group 10J/cm²); GIV (LED group 6 J/cm²); and GV (LED 10J/cm²). Photobiomodulation was performed on a daily basis for eight consecutive days and the local temperature was measured before and after phototherapy. After euthanasia the tissues were subjected to tensiometric and histological analysis. RESULTS: All irradiated groups showed increase in break strength (p = 0.009), and decrease in tissue deformation strength compared with the control group (p = 0.03). CONCLUSION: Both LILT and LED can promote wound healing at the tested doses with increased tissue resistance, although its elasticity is reduced. The imprecision of the assessing instruments precluded an accurate measurement of a possible local tissue heating post irradiation and future studies are need to elucidate this effect.