The Study of Tau Protein and Gene Expression in the Serum and Brain Tissue of Wistar Alzheimer’s Model Rats Treated with Probiotic Lactobacillus and Bifidobacter Strains

Alzheimer's disease is a type of brain dysfunction in which the patient's mental abilities, including memory gradually decline. The formation of neurofibrillary tangles inside neurons caused by hyperphosphorylation of tau proteins is a major cause of dementia-related diseases such as Alzheimer's. The aim of this study was to study tau protein in the brain and tau gene expression in both the serum level and brain tissue of Wistar Alzheimer's rats treated with probiotic strains of Lactobacillus and Bifidobacterium purified from yogurt. In this study, 30 adult male Wistar rats were randomly divided into 5 groups (n = 6): The control group, the group of Alzheimer's-induced rats, the Sham group, and the two experimental groups in which the Alzheimer's-induced rats received the probiotic strains Limosilactobacillus reuteri and Bifidobacterium longum at a dose of 2.5 × 109 CFU for one month, respectively. Tau gene expression and protein were analyzed by Real Time PCR and histopathology, respectively. The results of this study showed that both strains, especially Bifidobacterium longum, were able to reduce Tau gene expression in brain tissue and blood serum compared to Alzheimer's group. Also, both strains, especially Bifidibacterium longum, exhibited capability in inhibiting Tau neurofibrillary tangles. It seems that the probiotic strains Limosilactobacillu sreuetri and Bifidobacterium longum can be good candidates for reducing the Tau gene expression as well as Tau neurofibrillary tangles in Alzheimer's disease.