Comparative Analysis of the Number of Neurofilaments in Rat Sciatic Nerve Undergoing Neuropraxia Treated by Low-Level Laser and Therapeutic Ultrasound

Therapy by low-level laser (LLL) or ultrasound (US) are commonly used as treatment after nerve crush. The aim of this study was to determine the effectiveness of such treatments to repair the neuronal cytoskeleton evaluating the variation in the number of neurofilaments. For this an experimental design was performed, which involved 30 rats divided into 6 groups: 1 - control healthy; 2 - control injured; 3 - irradiated by LLL 2 J/cm2; 4 - irradiated by LLL 10 J/cm2; 5 - irradiated by US 0.5 W/cm2 and 6 irradiated by US 1W/cm2. With the exception of group 1 all specimens were anesthetized and underwent right sciatic nerve compression using 40N pressure for 45 seconds. Twenty-four hours after compression irradiation was started by LLL and US according protocol. In our research we found that the increase in the number of neurofilaments was related to the applied dose of LLL and US. The average value of neurofilaments / 0.25 mm2 obtained in each group was: 1- 28; 2-100; 3-156; 4-140; 5-100; 6-148. We concluded that the application of LLL and therapeutic US increases the number of neurofilaments in rat sciatic nerve undergoing neuropraxia, with LLL being more effective compared to the US. Furthermore we concluded that the effectiveness of therapies to induce regeneration of injured nerve is related to the type of protocol used, demonstrating the need to establish an adequate radiation dose with the purpose of obtaining the best therapeutic response, thus achieving successful treatment.