Abstract 16251: Neuroprotection by Near-infrared Light in a Rat Stroke Model
Introduction: Intravenous tissue Plasminogen Activator (tPA) is the only FDA approved pharmacological therapy for stroke. However, tPA can only be administered within 4.5 hours post stroke, and intracerebral hemorrhage remains a serious complication, severely limiting the use of tPA. Photobiomodulation (PBM) stimulates healing and repair of injuries by lowering swelling and inflammation. Targeting mitochondria, PBM results in modulation of reactive oxygen species, increased ATP production, activation of transcriptional factors, increased nitric oxide release and prevention of apoptotic cell death. Studies using ~809 nm light-emitting diodes (LED) have reported mixed results in animals and human clinical trials.
Hypothesis: The use of 670 nm LED PBM rescues locomotor function in a rat model of ischemic stroke.
Methods: A heat blunted nylon monofilament suture was introduced into the left common carotid artery and fed through the internal carotid artery into the middle cerebral artery of anesthetized male Sprague Dawley rats. Occlusion was maintained for 60 min and reperfusion achieved by removal of the filament. A 670 nm LED was used directly on top of the skull. One 90 sec treatment with a hand-held WARP10 device (Quantum Devices, Barneveld, WI, USA) delivered a power density of 50 mW/cm2 and a dose of 4 J/cm2. The light was administered at reperfusion, 2 hrs post and 24 hrs post reperfusion. Behavior was recorded in a Phenotyper cage pre and 24 hrs post stroke and analyzed using specialized software. Rats were euthanized 24 hrs post stroke, and their brains removed for infarct volume assessment by triphenyltetrazolium chloride staining. Statistics: ANOVA with Newman-Keuls post hoc test. Data are mean ± SEM, significance accepted at p < 0.05.
Results: Rats treated with 670 nm LED PBM had significantly reduced infarct volumes compared to stroke alone (64±16% vs 83±14%). In addition, LED-treated rats showed better recovery of locomotor function: distance moved (sham control 3133±291, stroke 704±254, stroke+LED 3693±1953 cm).
Conclusions: Our data suggest a potential neuroprotective role of 670 nm LED PBM in a rat experimental model of stroke.
Author Disclosures: A. Afzal: None. J.T. Eells: None. M. Salzman: None. M. Riess: None.
- © 2015 by American Heart Association, Inc.