Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2014 Aug 13;9(8):e103348.
doi: 10.1371/journal.pone.0103348. eCollection 2014.

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

Chau-Zen Wang  1 , Yi-Jen Chen  2 , Yan-Hsiung Wang  3 , Ming-Long Yeh  4 , Mao-Hsiung Huang  5 , Mei-Ling Ho  1 , Jen-I Liang  4 , Chia-Hsin Chen  6
Affiliations

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

Chau-Zen Wang et al. PLoS One. .

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/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.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. The 3 J/cm2 and 8 J/cm2 LLLT treatments improved the sciatic functional index (SFI) in rats with a sciatic nerve crush injury.
Representative images of (A) the sham-operated rat left hindlimb and (B) the sciatic-injured rat right hindlimb. (C) Functional assessment of the recovery of injured sciatic nerves by calculating the SFI in the normal rats without (normal) or with 8 J/cm2 LLLT (normal+8J) and in the sciatic nerve-crushed rats without (crush) or with LLLT at 3 J/cm2 (crush+3J), 8 J/cm2 (crush+8J) or 15 J/cm2 (crush+15J). *P<0.05, compared with crush group.
Figure 2
Figure 2. The 8 J/cm2 dosage of 808-nm laser enhanced the range of motion (ROM).
(A) Representative images show the sham-operated left rat hindlimb at mid-stance phase and (B) the sciatic-injured right rat hindlimb at mid-stance phase. (C) Functional assessment of the recovery of the injured sciatic nerve using ROM analysis by comparing the right hindlimb with the left hindlimb (ratio) in the normal rats without (normal) or with 8 J/cm2 LLLT (normal+8J) and in the sciatic nerve-crushed rats without (crush) or with LLLT at 3 J/cm2 (crush+3J), 8 J/cm2 (crush+8J) or 15 J/cm2 (crush+15J). *P<0.05, compared with the crush group.
Figure 3
Figure 3. LLLT-treated (808 nm) sciatic nerve presented thicker myelin sheaths.
Representative TEM images (A) and quantitative analyses of myelin sheath thickness (B) in the sciatic nerves of sham-operated rats without (normal) or with 8 J/cm2 LLLT (normal+8J) and in the rats with sciatic nerve crush injury without (crush) or with LLLT at 3 J/cm2 (crush+3J), 8 J/cm2 (crush+8J) or 15 J/cm2 (crush+15J). #P<0.05, compared with the crush group. Scale bar, 5 um.
Figure 4
Figure 4. Detection of GAP43 protein expression in rats with sciatic nerve crush injury after 808-nm LLLT treatments using western blot analysis.
Representative western blotting and quantitative analyses of GAP43 protein expression in the sciatic nerve of normal rats with 8 J/cm2 LLLT (normal+8J) and in the rats with sciatic nerve crush injury without (crush) or with LLLT at 3 J/cm2 (crush+3J), 8 J/cm2 (crush+8J) or 15 J/cm2 (crush+15J) were shown. We detected the expression of the GAP43 protein in the sciatic nerve of left sham-operated hindlimb (left normal control; N) and in the sciatic nerve of right hindlimb at the laser-treated site (T) or a distal site (D). *P<0.05, **P<0.01, compared with the left sham-operated hindlimb (left normal control; N). #P<0.05, compared with the crush group at the laser-treated site (T). &P<0.05, compared between the crush groups at the distal site (D).
Figure 5
Figure 5. Detection of GAP43 expression in the sciatic nerve of 808-nm LLLT laser-treated site using immunofluorescent staining.
Groups: sham-operated rats without (normal) or with 8 J/cm2 LLLT (normal+8J) and rats with sciatic nerve crush injury without (crush) or with LLLT at 3 J/cm2 (crush+3J), 8 J/cm2 (crush+8J) or 15 J/cm2 (crush+15J). Sections were labeled with DAPI (blue), GAP43 (green) and neurofilament (red), which is specifically expressed in neurites. Original magnification: 100×. White boxes show the enlarged views with a magnification of 400×. Scale bar, 200 um.
Figure 6
Figure 6. Detection of GAP43 expression in the sciatic nerve of 808-nm LLLT laser-treated distal site using immunofluorescent staining.
Groups: sham-operated rats without (normal) or with 8 J/cm2 LLLT (normal+8J) and rats with sciatic nerve crush injury without (crush) or with LLLT at 3 J/cm2 (crush+3J), 8 J/cm2 (crush+8J) or 15 J/cm2 (crush+15J). Sections were labeled with DAPI (blue), GAP43 (green) and neurofilament (red), which is specifically expressed in neurites. Original magnification: 100×. White boxes show the enlarged views with a magnification of 400×. Scale bar, 200 um.
See this image and copyright information in PMC

References

    1. Navarro X, Vivo M, Valero-Cabre A (2007) Neural plasticity after peripheral nerve injury and regeneration. Prog Neurobiol 82: 163–201. - PubMed
    1. Allodi I, Udina E, Navarro X (2012) Specificity of peripheral nerve regeneration: interactions at the axon level. Prog Neurobiol 98: 16–37. - PubMed
    1. Navarro X, Vivó M, Valero-Cabré A (2007) Neural plasticity after peripheral nerve injury and regeneration. Progress in Neurobiology 82: 163–201. - PubMed
    1. Colen KL Choi M, Chiu DT (2009) Nerve grafts and conduits. Plast Reconstr Surg 124: e386–394. - PubMed
    1. Gu X, Ding F, Yang Y, Liu J (2011) Construction of tissue engineered nerve grafts and their application in peripheral nerve regeneration. Prog Neurobiol 93: 204–230. - PubMed

Publication types

MeSH terms