B. breve + L. casei Combo Reduces Brain Aging in Mice

study PMID: 40457028

Quick Summary: A new study found that a combination of Bifidobacterium breve and Lactobacillus casei helped reduce signs of brain aging in mice. The combination worked better than either probiotic alone, showing promise for future research on brain health.

What The Research Found

Researchers studied mice to see how probiotics could help with brain aging. They found that giving mice a mix of Bifidobacterium breve and Lactobacillus casei improved their memory and reduced brain damage. The combination of probiotics worked even better than giving the mice just one type of probiotic. This suggests that combining probiotics could be a good way to protect the brain as we get older.

Study Details

Who was studied: Male mice were used in this study.

How long: The mice were given probiotics for 8 weeks.

What they took: The mice received either B. breve, L. casei, or a combination of both, along with a substance to speed up aging.

What This Means For You

This research is exciting, but it's important to remember that it was done on mice. It suggests that a combination of B. breve and L. casei might help protect the brain, but we don't know if it will work the same way in humans. More research is needed before we can recommend these probiotics for people. If you're interested in probiotics, talk to your doctor.

Study Limitations

The study was done on mice, not people.

The exact amount of probiotics given to the mice wasn't specified.

Only male mice were used, so the results might be different for females.

The study used a method to speed up aging, which may not fully reflect how the brain ages naturally.

Key Findings

The study demonstrated that co-administration of Lactobacillus casei (L. casei) and Bifidobacterium breve (B. breve) outperformed monotherapy in mitigating hippocampal neurodegeneration in aged mice. Both probiotics individually improved Y-maze alternation and locomotion behavior (indicating enhanced spatial memory and motor function), but the combination showed synergistic effects. Molecular analysis revealed significant upregulation of neuroprotective genes (α-KL, Sirt1, HO-1, Nrf2) and suppression of pro-inflammatory cytokines (IL-1β, IL-18) in the right hippocampus. Oxidative stress markers (malondialdehyde/MDA) were significantly reduced, while antioxidant superoxide dismutase (SOD) activity increased. Histopathological improvements and elevated BDNF fluorescence intensity confirmed reduced neurodegeneration. L. casei monotherapy exhibited stronger effects than B. breve alone.

Study Design

This was an in vivo preclinical study using a D-galactose-induced aging mouse model. Male Balb/C mice (sample size unspecified in summary) received subcutaneous D-galactose injections to accelerate aging, followed by 8 weeks of oral probiotic supplementation. Groups included: control, D-galactose-only, D-galactose + L. casei, D-galactose + B. breve, and D-galactose + L. casei/B. breve combination. Behavioral (Y-maze), molecular (qPCR for gene expression), biochemical (MDA/SOD assays), and histopathological analyses were conducted post-intervention.

Dosage & Administration

The study administered probiotics orally via gavage for 8 weeks. Specific colony-forming unit (CFU) doses were not detailed in the provided summary. Probiotics were delivered daily alongside D-galactose-induced aging.

Results & Efficacy

Behavioral: All probiotic groups showed significant improvement in Y-maze spontaneous alternation (p<0.05 vs. D-galactose-only), with combination therapy yielding the strongest effect.
Molecular: α-KL, Sirt1, HO-1, and Nrf2 expression increased significantly (p<0.05), while IL-1β and IL-18 decreased (p<0.05) in probiotic groups. Combination therapy amplified these changes.
Oxidative Stress: MDA levels significantly decreased (p<0.05), and SOD activity increased (p<0.05) across probiotic groups, most markedly with co-administration.
Neurodegeneration: Histopathology revealed reduced neuronal damage in the left hippocampus. BDNF fluorescence intensity was significantly higher (p<0.05) in all probiotic groups versus D-galactose-only controls.

Limitations

The study used a mouse model, limiting direct human applicability. Sample sizes per group were not specified, raising concerns about statistical power. Only male mice were tested, excluding sex-based variability. Doses and strain-specific CFU counts were unreported, hindering reproducibility. The D-galactose model mimics accelerated aging but not natural aging processes. Mechanistic links between gut microbiota changes and brain outcomes were not fully elucidated.

Clinical Relevance

This preclinical evidence suggests that B. breve and L. casei combinations may offer superior neuroprotection against age-related cognitive decline compared to single strains, potentially via anti-inflammatory and antioxidant pathways. However, human trials are essential before clinical recommendations. Supplement users should note that effective doses, strain specificity, and long-term safety in humans remain unverified. Current findings support further research into multi-strain probiotics for brain health but do not justify self-administration for neurodegenerative conditions.

B. breve + L. casei Combo Reduces Brain Aging in Mice