Investigating the Effect of Local Probiotics Strains on β-Amyloid Brain Biomarker in Induced Alzheimer’s-Disease Wistar Rats

One of the most important causes of global population decline is the overgrowth of neurodegenerative diseases, including Alzheimer's disease characterized by the extracellular accumulation of amyloid beta (Aβ) plaques in the hippocampus. Probiotics are microscopic organisms that are important for maintaining and improving human health. This study aims at assessing the effect of two probiotic strains, including Bifidobacterium longum and Limosilactobacillus reuteri on Aβ42 gene expression, the count of amyloid plaques, and neurogenesis in the brain of Alzheimer's disease rat models. First, two probiotic strains were isolated, purified and identified from traditional yogurt, and the rats were grouped as follows: thirty male Wistar rats were randomly divided into 5 groups. The control group underwent any surgery with no special treatment. The other groups underwent surgery and after being injected by Aβ42, they were divided into the sham group receiving water (probiotics solvent) and the two experimental groups receiving 2.5 x 109 CFU of Bifidobacterium longum and Limosilactobacillus reuteri strains. Finally, Aβ42 gene expression, the count of amyloid plaques, and neurogenesis were assessed in the brain of Alzheimer's disease rat models. In the brain of induced Alzheimer’s disease rats, neuron death occurred and the number of amyloid plaques increased significantly (p<0.001). Also, Aβ42 gene expression was increased in their brains. Meanwhile, treatment with both probiotic strains notably improved all of these symptoms. Therefore, the use of both Bifidobacterium longum and Limosilactobacillus reuteri probiotic strains seem to be effective in the recovery and treatment of Alzheimer's disease which certainly requires more investigations.