Peripheral nerves are often exposed to injuries from traumatic origins, such as crushing impact and total transections, resulting in decreases or complete loss of sensory and motor capabilities in corresponding area of innervations. Laser irradiation is one of the therapeutic methods for the recovery of degenerated peripheral nerves. The present study focuses on the effect of 780 nm laser irradiation on the regeneration of injured sciatic nerves after end to end anastomosis in the rabbit. Twenty adult white New Zealand male rabbits were used, where the injury of the type axontmesis of the right sciatic nerve under general anesthesia was approximated using proline 6-0. The rabbits were randomly distributed in 2 groups with 10 rabbits each. In group I, Arsenate of Gallium Laser with the extension of wave of 780 nm, 10 mW power with 1.0 J/cm2 irradiation with 10 seconds for each Cm2 with penetration of 4cm, in the pulsed form. The laser therapy in group I was initiated on the post-surgical first day, where all the rabbits with application once a day for 15 days or 10 minutes each rabbit. Rabbits in group II not had given treatment (control group). The samples of transected nerves were collected and prepared of histological analysis on the 90 days, they were analyzed and quantitifid for Schwann cells, mylenic axons with larger diameter and neurons. The histological aspect was essentially normal on proximal segments of the right sciatic nerve on both experimental groups, with a regular distribution of narrow and wide nervous fibers and an apparently normal proportion between myelin sheaths thickness and fibers diameter, numerous nonmyelinated fibers, intraneural blood vessels, and fibroblasts were also observed. In the proximal and intermediate segments (injury site), blood vessels were more prevalent and thicker for group I than group II. Thick fibers with very thin myelin sheaths were prevalent in the intermediate segment in both groups I and II. Schwann cells with reactive appearance nuclei, characteristic of synthesis activity, as well as typical images of axonal sprouting were more prevalent on group I, while Wallerian degeneration was more evident on group II. Small-gauge fibers and thin myelin sheaths were prevalent, although thick fibers and thick myelin sheaths were also frequent on group II next to a large number of Schwann cells with reactive-appearance nucleus and images of axonal sprouting. In this segment, Wallerian degeneration was not so evident for group I and even II. This study suggests that postoperative low-power Ga-As-Al laser irradiation was able to accelerate and potentialize the peripheral nerve regeneration process of rabbits within 15 days of irradiation.
