Gut flora-targeted photobiomodulation therapy improves senile dementia in an Aß-induced Alzheimer's disease animal model

Qianqian Chen; Jinpeng Wu; Xiaoxi Dong; Huijuan Yin; Xiafei Shi; Siying Su; Bochen Che; Yingxin Li; Jichun Yang

doi:10.1016/j.jphotobiol.2021.112152

Gut flora-targeted photobiomodulation therapy improves senile dementia in an Aß-induced Alzheimer's disease animal model

J Photochem Photobiol B. 2021 Mar:216:112152. doi: 10.1016/j.jphotobiol.2021.112152. Epub 2021 Feb 10.

Authors

Qianqian Chen¹, Jinpeng Wu², Xiaoxi Dong², Huijuan Yin³, Xiafei Shi², Siying Su², Bochen Che², Yingxin Li⁴, Jichun Yang²

Affiliations

¹ Laser Medicine Laboratory, Institute of Biomedical Engineering, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin 300192, China; Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing 100176, China.
² Laser Medicine Laboratory, Institute of Biomedical Engineering, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin 300192, China.
³ Laser Medicine Laboratory, Institute of Biomedical Engineering, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin 300192, China. Electronic address: yinzi490@163.com.
⁴ Laser Medicine Laboratory, Institute of Biomedical Engineering, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin 300192, China. Electronic address: yingxinli2005@126.com.

PMID: 33610085
DOI: 10.1016/j.jphotobiol.2021.112152

Abstract

Background: Emerging evidence suggests that the gut microbiota plays an important role in the pathological progression of Alzheimer's disease (AD). Photobiomodulation (PBM) therapy is believed to have a positive regulatory effect on the imbalance of certain body functions, including inflammation, immunity, wound healing, nerve repair, and pain. Previous studies have found that the intestinal flora of patients with AD is in an unbalanced state. Therefore, we have proposed the use of gut flora-targeted PBM (gf-targeted PBM) as a method to improve AD in an Aß-induced AD mouse model.

Methods: PBM was performed on the abdomen of the mice at the wavelengths of 630 nm, 730 nm, and 850 nm at 100 J/cm² for 8 weeks. Morris water maze test, immunofluorescence and proteomic of hippocampus, and intestinal flora detection of fecal were used to evaluate the treatment effects of gf-targeted PBM on AD rats.

Results: PBM at all three wavelengths (especially 630 nm and 730 nm) significantly improved learning retention as measured by the Morris water maze. In addition, we found reduced amyloidosis and tau phosphorylation in the hippocampus by immunofluorescence in AD mice. By using a quantitative proteomic analysis of the hippocampus, we found that gf-targeted PBM significantly altered the expression levels of 509 proteins (the same differentially expressed proteins in all three wavelengths of PBM), which involved the pathways of hormone synthesis, phagocytosis, and metabolism. The 16 s rRNA gene sequencing of fecal contents showed that PBM significantly altered the diversity and abundance of intestinal flora. Specifically, PBM treatment reversed the typical increase of Helicobacter and uncultured Bacteroidales and the decrease of Rikenella seen in AD mice.

Conclusions: Our data indicate that gf-targeted PBM regulates the diversity of intestinal flora, which may improve damage caused by AD. Gf-targeted PBM has the potential to be a noninvasive microflora regulation method for AD patients.

Keywords: Alzheimer's disease; Gastrointestinal microbiome; Photobiomodulation therapy; Proteomics.

MeSH terms

Alzheimer Disease* / radiotherapy
Amyloidosis / radiotherapy
Animals
Disease Models, Animal
Gastrointestinal Microbiome* / radiation effects
Hippocampus / radiation effects
Humans
Low-Level Light Therapy* / methods
Male
Mice
Morris Water Maze Test / radiation effects
Phosphorylation / radiation effects
Proteomics
Rats
tau Proteins / metabolism

Substances

tau Proteins