Assessment of Functional Recovery of Sciatic Nerve in Rats Submitted to Low-Level Laser Therapy with Different Fluences. An Experimental Study

Abstract

Peripheral nerve lesions caused sensory and motor deficits along the distribution of the injured nerve. Numerous researches have been carried out to enhance and/or accelerate the recovery of such lesions. The objective of this study was to assess the functional recovery of sciatic nerve in rats subjected to different fluences of low-level laser therapy (LLLT). Thirty-six animals were randomly divided into four groups: one consisting of sham rats and three others irradiated with progressive fluencies of 10J/cm(2), 40J/cm(2) and 80J/cm(2) of laser AsGaAl (830nm) for 21 consecutive days. They were evaluated by the Sciatic Functional Index (SFI) method. The crush injury was performed by using a portable device with dead weight of 5,000g whose load was applied for 10min. A digital camera was used to record the footprints left on the acrylic track, before surgery and after, on the 7th, 14th, and 21st days. The results also showed that on the 7th day, there was a difference between the groups irradiated with 40J/cm(2), when compared with the sham group (p < 0.05). On the 14th day the groups irradiated with 40J/cm(2) and 80J/cm(2) also presented better results when compared with sham, however, on the 21st day, no inter-group difference was found (p > 0.05). It was possible to observe that the LLLT at fluency of 40J/cm(2) and 80J/cm(2) had a positive influence on the acceleration of the functional nerve recovery.