Low-level laser therapy for beta amyloid toxicity in rat hippocampus.
Beta amyloid (Aβ) is well accepted to play a central role in the pathogenesis of Alzheimer's disease (AD). The present work evaluated the therapeutic effects of low-level laser irradiation (LLI) on Aβ-induced neurotoxicity in rat hippocampus. Aβ 1-42 was injected bilaterally to the hippocampus CA1 region of adult male rats, and 2-minute daily LLI treatment was applied transcranially after Aβ injection for 5 consecutive days. LLI treatment suppressed Aβ-induced hippocampal neurodegeneration and long-term spatial and recognition memory impairments. Molecular studies revealed that LLI treatment: (1) restored mitochondrial dynamics, by altering fission and fusion protein levels thereby suppressing Aβ-induced extensive fragmentation; (2) suppressed Aβ-induced collapse of mitochondrial membrane potential; (3) reduced oxidized mitochondrial DNA and excessive mitophagy; (4) facilitated mitochondrial homeostasis via modulation of the Bcl-2-associated X protein/B-cell lymphoma 2 ratio and of mitochondrial antioxidant expression; (5) promoted cytochrome c oxidase activity and adenosine triphosphate synthesis; (6) suppressed Aβ-induced glucose-6-phosphate dehydrogenase and nicotinamide adenine dinucleotide phosphate oxidase activity; (7) enhanced the total antioxidant capacity of hippocampal CA1 neurons, whereas reduced the oxidative damage; and (8) suppressed Aβ-induced reactive gliosis, inflammation, and tau hyperphosphorylation. Although development of AD treatments has focused on reducing cerebral Aβ levels, by the time the clinical diagnosis of AD or mild cognitive impairment is made, the brain is likely to have already been exposed to years of elevated Aβ levels with dire consequences for multiple cellular pathways. By alleviating a broad spectrum of Aβ-induced pathology that includes mitochondrial dysfunction, oxidative stress, neuroinflammation, neuronal apoptosis, and tau pathology, LLI could represent a new promising therapeutic strategy for AD.
Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA.
Yujiao
Y
Lu
Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA; Neurobiology Institute of Medical Research Center, North China University of Science and Technology, Tangshan, China. Electronic address: minruiwang@gmail.com.
Ruimin
R
Wang
Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA.
Yan
Y
Dong
Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA.
Donovan
D
Tucker
Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA.
Ningjun
N
Zhao
Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA.
Md Ejaz
ME
Ahmed
Laboratory of Laser Sports Medicine, College of Physical Education and Sports Science, South China Normal University, Guangzhou, China.
Ling
L
Zhu
Laboratory of Laser Sports Medicine, College of Physical Education and Sports Science, South China Normal University, Guangzhou, China.
Timon Cheng-Yi
TC
Liu
Department of Psychiatry and Behavioral Sciences and Neuroscience Program, Emory University, Atlanta, GA, USA.
Robert M
RM
Cohen
Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA. Electronic address: qzhang@gru.edu.
Quanguang
Q
Zhang
D000544:Alzheimer Disease / Q000209:etiology* / Q000523:psychology / Q000532:radiotherapy*; D016229:Amyloid beta-Peptides / Q000378:metabolism* / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis; D056547:CA1 Region, Hippocampal / Q000378:metabolism* / Q000473:pathology; D007249:Inflammation; D054023:Lasers, Semiconductor / Q000627:therapeutic use; D028022:Low-Level Light Therapy / Q000379:methods; D008297:Male; D063154:Mitochondrial Dynamics; D009474:Neurons / Q000473:pathology; D018384:Oxidative Stress; D010446:Peptide Fragments / Q000378:metabolism* / Q000633:toxicity*; D017207:Rats, Sprague-Dawley; D021641:Recognition, Psychology; D065852:Spatial Memory; D024801:Tauopathies / Q000209:etiology / Q000532:radiotherapy
D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42)
Alzheimer's disease; Cognition; Inflammation; Low-level laser therapy; Mitochondrial dysfunction