Elsevier

Behavioural Brain Research

Volume 298, Part B, 1 February 2016, Pages 202-209
Behavioural Brain Research

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

https://doi.org/10.1016/j.bbr.2015.10.046Get rights and content
Under a Creative Commons license
open access

Highlights

  • Both live and heat-killed PS128 showed no obvious toxic effects to the germ-free (GF) mice.

  • Live PS128 increased locomotor activity of the GF mice.

  • Live PS128 reduced anxiety-like behavior of the GF mice in the elevated plus maze.

  • Live PS128 increased both dopamine and serotonin level in the striatum.

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.

Abbreviations

ALT
alanine aminotransferase
CPK
creatine phosphokinase
CREA
creatinine
DA
dopamine
EPM
elevated plus maze
FST
forced swim test
GBA
gut–brain axis
GF
germ-free
HPLC–ECD
high-performance liquid chromatography with electrochemical detection system
MRS
Man Rogosa Sharpe
NA
noradrenaline
OFT
open field test
SPF
specific pathogen-free
TG
triacylglycerol

Keywords

Anxiety
Dopamine
Germ-free mice
Lactobacillus plantarum
Locomotor
Serotonin

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