Alteration of behavior and monoamine levels attributable to Lactobacillus plantarum PS128 in germ-free mice

Abstract

Probiotics, defined as live bacteria or bacterial products, confer a significant health benefit to the host, including amelioration of anxiety-like behavior and psychiatric illnesses. Here we administered Lactobacillus plantarum PS128 (PS128) to a germ-free (GF) mouse model to investigate the impact of the gut-brain axis on emotional behaviors. First, we demonstrated that chronic administration of live PS128 showed no adverse effects on physical health. Then, we found that administration of live PS128 significantly increased the total distance traveled in the open field test and decreased the time spent in the closed arm in the elevated plus maze test, whereas the administration of PS128 had no significant effects in the depression-like behaviors of GF mice. Also, chronic live PS128 ingestion significantly increased the levels of both serotonin and dopamine in the striatum, but not in the prefrontal cortex or hippocampus. These results suggest that the chronic administration of PS128 is safe and could induce changes in emotional behaviors. The behavioral changes are correlated with the increase in the monoamine neurotransmitters in the striatum. These findings suggest that daily intake of the L. plantarum strain PS128 could improve anxiety-like behaviors and may be helpful in ameliorating neuropsychiatric disorders.

Effect of Probiotics on Central Nervous System Functions in Animals and Humans: A Systematic Review

“…23,35 Two studies using Lactobacillus plantarum also found alleviated anxiety levels in mice after the intervention. 20,21 Bifidobacterium breve and Lactobacillus fermentum were used once each and showed anxiolytic effects. 30,36 Two studies using multi-strain probiotic combinations of L. rhamnosus + L. helveticus and B. longum + L. helveticus found reduced anxious behavior.…”

“…23,26,27,36,40 Two studies tested L. plantarum, but it only had an effect in mice with the early life stress of maternal separation. 20,21 One study used a multi-strain combination of B.…”

Psychobiotics: Next Generation Treatment for Mental Disorders

“…There are three suggested mechanisms for probiotics effects on mental health: The first way is referred to the probiotics ability in secretion of neurotransmitters such as gamma-aminobutyric acid (GABA), serotonin, catecholamines, and acetylcholine in the gut and notice brain function and affect behavior. Studies indicated that a considerable portion of brain chemicals like serotonin, GABA, dopamine, and acetylcholine produces in the intestines by gut microbiota [2,3,[7][8][9].…”

“…Studies showed that Lactobacillus plantarum (strain PS128) can cause positive changes in emotional behaviors and significantly reduce anxiety-like behaviors through increasing dopamine and serotonin, lowering stress hormone levels, and reducing inflammation [7].…”

Toxicity Studies of Lactobacillus plantarum PS128TM Isolated from Spontaneously Fermented Mustard Greens

“…In naïve mice, locomotor activity was increased, and anxiety-like behavior was decreased upon PS128 TM treatment. Prefrontal cortex analysis showed increased levels of dopamine and serotonin [11], suggesting that daily intake of PS128 TM exerts psychotropic effects that could reduce anxiety-like behavior and may be helpful in alleviating neuropsychiatric disorders by decreasing stress-related symptoms. Recently, evidence also showed that there are potentials for PS128 TM to improve cerebral dopamine-related symptoms in mice such as Tourette syndrome [12].…”