Low-level laser irradiation improves functional recovery and nerve regeneration in sciatic nerve crush rat injury model

PLoS One. 2014 Aug 13;9(8):e103348. doi: 10.1371/journal.pone.0103348. eCollection 2014.


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/cm(2) and a sciatic nerve crush injury group with or without 808-nm LLLT at 3, 8 or 15 J/cm(2). 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/cm(2) had significantly improved SFI but that a significant improvement of ROM was only found in rats with LLLT at 8 J/cm(2). 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/cm(2). Taken together, these results suggest that 808-nm LLLT at a low energy density (3 J/cm(2) and 8 J/cm(2)) is capable of enhancing sciatic nerve regeneration following a crush injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • GAP-43 Protein / metabolism
  • Hindlimb / physiopathology
  • Infrared Rays / therapeutic use*
  • Low-Level Light Therapy*
  • Male
  • Microscopy, Electron, Transmission
  • Myelin Sheath / radiation effects
  • Myelin Sheath / ultrastructure
  • Nerve Crush
  • Nerve Regeneration*
  • Range of Motion, Articular
  • Rats
  • Rats, Sprague-Dawley
  • Recovery of Function
  • Sciatic Nerve / injuries
  • Sciatic Nerve / physiology
  • Sciatic Nerve / radiation effects*
  • Sciatic Neuropathy / physiopathology
  • Sciatic Neuropathy / radiotherapy*


  • GAP-43 Protein

Grants and funding

This work was supported by grants from the National Health Research Institutes (NHRI-EX 102-9914EC), the National Science Council (101-2314-B-037-002-MY3) and the Kaohsiung Medical University Research Foundation (KMU-Q98007), Taiwan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.