RESUMEN
Given the complexity of the tendon repair process, where the neoformed scar tissue tends to prevent or hamper the tendon from performing its normal functions, ultrasound (US) and light-emitting diode (LED) devices have been applied to modulate the tendon repair process. This study aimed to compare the anti-inflammatory and healing effects of therapeutic US and LED in an experimental model of tenotomy using histomorphometry and Raman spectroscopy. Forty Wistar rats (235 ± 8.3 g) were separated into four groups: tenotomy (TC; control), tenotomy associated with ultrasound (US; 1 MHz, 0.5 W/cm(2)), tenotomy associated with LED at 625 nm (LR; 4 J/cm(2)), and tenotomy associated with LED at 945 nm (LIR; 4 J/cm(2)), in two experimental periods of 7 and 14 days. Histomorphometry showed a decrease of inflammatory cells (macrophages and polymorphonuclear leukocytes) for the group treated with US compared to the TC group (ANOVA, p < 0.0001) and the LIR group compared to the TC group (p < 0.05) at the seventh day, indicating an anti-inflammatory effect. In relation to the LR and TC groups, there was no significant difference. Raman spectroscopy revealed that the LR group presented an increased synthesis of collagen I compared to the other treatments and the TC groups on the 14th day (p < 0.01). US therapy showed an adjuvant effect with anti-inflammatory action, and the LED therapy at 625 nm showed an increase in collagen synthesis, contributing to the process of tendon healing.