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J Biophotonics. 2015 Jun;8(6):502-11. doi: 10.1002/jbio.201400069. Epub 2014 Sep 8.

Low-level laser therapy for traumatic brain injury in mice increases brain derived neurotrophic factor (BDNF) and synaptogenesis.

Xuan W1,2,3, Agrawal T2,3, Huang L2,3,4, Gupta GK2,3,5, Hamblin MR6,7,8.

Author information

1
Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom Street, Boston, MA 02114, USA.
2
Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA.
3
Department of Otolaryngology, Traditional Chinese Medical University of Guangxi, Nanning, China.
4
Department of Infectious Diseases, First Affiliated College & Hospital, Guangxi Medical University, Nanning, 530021, China.
5
Department of Pathology and Laboratory Medicine, Tufts Medical Center, Boston, MA 02111, USA.
6
Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA. hamblin@helix.mgh.harvard.edu.
7
Department of Otolaryngology, Traditional Chinese Medical University of Guangxi, Nanning, China. hamblin@helix.mgh.harvard.edu.
8
Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA. hamblin@helix.mgh.harvard.edu.

Abstract

Transcranial low-level laser (light) therapy (LLLT) is a new non-invasive approach to treating a range of brain disorders including traumatic brain injury (TBI). We (and others) have shown that applying near-infrared light to the head of animals that have suffered TBI produces improvement in neurological functioning, lessens the size of the brain lesion, reduces neuroinflammation, and stimulates the formation of new neurons. In the present study we used a controlled cortical impact TBI in mice and treated the mice either once (4 h post-TBI, 1-laser), or three daily applications (3-laser) with 810 nm CW laser 36 J/cm(2) at 50 mW/cm(2). Similar to previous studies, the neurological severity score improved in laser-treated mice compared to untreated TBI mice at day 14 and continued to further improve at days 21 and 28 with 3-laser being better than 1-laser. Mice were sacrificed at days 7 and 28 and brains removed for immunofluorescence analysis. Brain-derived neurotrophic factor (BDNF) was significantly upregulated by laser treatment in the dentate gyrus of the hippocampus (DG) and the subventricular zone (SVZ) but not in the perilesional cortex (lesion) at day 7 but not at day 28. Synapsin-1 (a marker for synaptogenesis, the formation of new connections between existing neurons) was significantly upregulated in lesion and SVZ but not DG, at 28 days but not 7 days. The data suggest that the benefit of LLLT to the brain is partly mediated by stimulation of BDNF production, which may in turn encourage synaptogenesis. Moreover the pleiotropic benefits of BDNF in the brain suggest LLLT may have wider applications to neurodegenerative and psychiatric disorders. Neurological Severity Score (NSS) for TBI mice.

KEYWORDS:

BDNF; Synapsin-1; neurogenesis; synaptogenesis; transcranial low level light therapy; traumatic brain injury

PMID:
25196192
PMCID:
PMC5379854
DOI:
10.1002/jbio.201400069
[Indexed for MEDLINE]
Free PMC Article

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