Table 1: Animal studies on evaluating the effects of Probiotics on Central Nervous System functions in various disease conditions

Disease target & Study Objective Animal Treatment /Intervention Outcome Conclusion
Depression
[50]
To study psychotropic effects of a potential psychobiotic bacterium, Lactobacillus plantarum strain PS128 (PS128), on mice subjected to early life stress (ELS) and on naïve adult mice. ELS mice
Naïve mice
L. plantarum PS128
109
28 days
Behavioral tests revealed that chronic ingestion of PS128 increased the locomotor activities in both ELS and naïve adult mice in the open field test. In the elevated plus maze, PS128 significantly reduced the anxiety-like behaviors in naïve adult mice but not in the ELS mice; whereas the depression-like behaviors were reduced in ELS mice but not in naïve mice in forced swimming test and sucrose preference test. Chronic ingestion of PS128 could ameliorate anxiety- and depression-like behaviors and modulate neurochemicals and has great potential for improving stress-related symptoms.
Stress related Anxiety Disorder
[51]
To study the effect of administration of Lactobacillus helveticus NS8 on behavioural, cognitive and biochemical aberrations caused by chronic restraint stress in SPF rats SPF CRS Rats L. helveticus NS8 (109 CFU/ml) for 21 days L. helveticus NS8 improved cognitive dysfunction and behaviour anxiety and depression with decrease in CPRT levels, ACTH levels, increase in IL-10 levels and restored levels of 5-HT and NE. Probiotic bacteria represents a potential target in relieving stress related behavioural problems.
Alzheimer’s
[52]
To study the effect of probiotic supplementation for 6 weeks in beta-amyloid induced rat model of Alzheimer's disease (AD) Rats
Beta-amyloid induced rat model
500 mg probiotic given daily by gavage for 4 weeks before and 2 weeks after beta-amyloid(1-42) administration Probiotic supplementation improved learning but not memory impairment, increase levels of PPF ratios were seen compared to the placebo group. Positive impact of probiotic administration on learning capacity and LTP in rats with AD like symptoms.
Depression
[53]
To study the effect of Bifidobacterium infantis in maternal separation model of depression Rats
(Rat maternal separation model)
Adult rat offsprings chronically treated with Citaopram or Bifidobacteria and then subjected to forced Swim test (FST) Probiotic treatment helped in normalisation of immune response, reversal of behavioural deficits, restored the noradrenaline levels in brains Potential therapeutic target to treat the symptom of depression
Autism spectrum disorder (ASD)
[54]
To study the gut-microbiota connection in a mouse model of ASD Offspring mice
(model of maternal immune activation; MIA)
Bacteriodes fraglis
NCTC9343;1010
6 days
Bacteriodes fraglis oral administration corrected gut permeability, ameliorates defects in anxiety and sensorimotor behavior in offspring mice Potential probiotic therapy for targeting autism defects and behavioral symptom display at an early age
Chronic fatigue syndrome (CFS)
[55]
To study the role of Lactobacillus acidophilus loaded floating alginate beads in improving chronic fatigue syndrome (CFS) Rats Per-oral administration of free LAB and LAB loaded alginate beads daily for 28 days (107 CFU/ml) Treatment with Lab and LAB loaded beads significantly decreased TNF-alpha levels, decrease in immobility and decrease in post swim fatigue during the forced swim test assay in animals. Valuable therapeutic role of LAB loaded alginate beads in the treatment against CFS.
Vascular Dementia (VaD)
[56]
To study the effect of administration of C.butyricum VaD mice C. butyricum WZMC1016 (CGMCC 9831) C. butyricum significantly attenuated the cognitive dysfunction and histopathological damage seen in VAD mice while decreasing the neuronal apoptosis and increased BDNF levels. Probiotic administration is a potential new therapeutic option to treat this disease

CORT, corticosterone; 5-HT, 5-hydroxytryptamine; ACTH, adrenocorticotropic hormone; NE, norepinephrine; BDNF, brain-derived neurotrophic factor; GABA, gamma-Aminobutyric acid; CFS, chronic fatigue syndrome; LAB, Lactobacillus acidophilus; VaD, vascular dementia; NF-κB, nuclear factor-kappa B; MIA, maternal immune activation; TNF: tumor necrosis factor; SPF:specific pathogen free