Low-Level Laser Irradiation Improves Functional Recovery and Nerve Regeneration in Sciatic Nerve Crush Rat Injury Model

Abstract

The development of noninvasive approaches to facilitate the regeneration of post-traumatic nerve injury is important for clinical rehabilitation. In this study, we investigated the effective dose of noninvasive 808-nm low-level laser therapy (LLLT) on sciatic nerve crush rat injury model. Thirty-six male Sprague Dawley rats were divided into 6 experimental groups: a normal group with or without 808-nm LLLT at 8 J/cm2 and a sciatic nerve crush injury group with or without 808-nm LLLT at 3, 8 or 15 J/cm2. Rats were given consecutive transcutaneous LLLT at the crush site and sacrificed 20 days after the crush injury. Functional assessments of nerve regeneration were analyzed using the sciatic functional index (SFI) and hindlimb range of motion (ROM). Nerve regeneration was investigated by measuring the myelin sheath thickness of the sciatic nerve using transmission electron microscopy (TEM) and by analyzing the expression of growth-associated protein 43 (GAP43) in sciatic nerve using western blot and immunofluorescence staining. We found that sciatic-injured rats that were irradiated with LLLT at both 3 and 8 J/cm2 had significantly improved SFI but that a significant improvement of ROM was only found in rats with LLLT at 8 J/cm2. Furthermore, the myelin sheath thickness and GAP43 expression levels were significantly enhanced in sciatic nerve-crushed rats receiving 808-nm LLLT at 3 and 8 J/cm2. Taken together, these results suggest that 808-nm LLLT at a low energy density (3 J/cm2 and 8 J/cm2) is capable of enhancing sciatic nerve regeneration following a crush injury.

The new heterologous fibrin sealant in combination with low-level laser therapy (LLLT) in the repair of the buccal branch of the facial nerve

“…Regarding the use of LLLT, the most effective laser application with regard to wavelength, energy density, exposure time, and pulsed or continuous wave is still controversial, but its use is suggested to facilitate the nerve regeneration [27,43]. Based in this study, on the statistical data, similar results were observed in most measured variables, when comparing EGS to EGSL and EGF to EGFL in both periods, but with mean values almost always favorable with laser therapy.…”

“…The laser source had been previously tested to certify the dose. The laser therapy applications were performed 1 day after surgery, and in the postoperative period, three times a week for a total of 5 weeks [27][28][29].…”

Photobiomodulation Therapy (PBMT) in Peripheral Nerve Regeneration: A Systematic Review

“…Among the effects of PBMT on nerve injury, it was verified that the laser minimized the side effects of bupivacaine on the nerve and on the muscle [29], potentiated the process of nerve regeneration observed by morpho-quantitative analysis of the axons and of the nerve fibers [2,3,19,30,31,32,33,34,35], in addition to assisting muscular reinnervation [36]. …”

The sciatic nerve injury model in pre-clinical research

“…Yet, high reproducibility of the lesion makes this experimental model also particularly suitable for investigating regeneration-related time course changes (De Leon et al, 1991;Gupta and Channual, 2006;Sta et al, 2014). Finally, changes in the outcome of nerve regeneration after a crush injury of the sciatic nerve might be used as a pre-clinical end-point predictor of the effectiveness of a therapeutic agent and/or tissue engineering strategy on nerve regeneration (Fleming et al, 2007;Amado et al, 2008;Baptista et al, 2008;Gigo-Benato et al, 2010;Dadon-Nachum et al, 2011;Kilic et al, 2013;Wang et al, 2014).…”