Probiotics normalize the gut-brain-microbiota axis in immunodeficient mice

Area of Science:

• Neuroscience
• Immunology
• Microbiology

Background:

• The gut-brain-microbiota axis is crucial for intestinal homeostasis.
• Psychological stress disrupts this axis, affecting gut barrier function, microbiota composition, and behavior.
• The role of the adaptive immune system in mediating these stress-induced changes is not fully understood.

Purpose of the Study:

• To investigate if the adaptive immune system mediates the effects of psychological stress on intestinal physiology and behavior.
• To determine if probiotic treatment can normalize these stress-induced alterations.
• To elucidate the role of lymphocytes in maintaining gut-brain-microbiota axis health.

Main Methods:

• Utilized B and T cell-deficient Rag1(-/-) mice to assess the impact of immune deficiency on stress response.
• Evaluated behavioral changes (anxiety, memory), HPA axis activity, intestinal secretory state, and gut microbiota composition.
• Assessed hippocampal c-Fos expression as a marker of neuronal activity.
• Administered probiotics to evaluate their therapeutic potential.

Main Results:

• Rag1(-/-) mice exhibited altered baseline behaviors, an overactive HPA axis, increased intestinal secretion, and gut dysbiosis.
• Hippocampal c-Fos expression was decreased in Rag1(-/-) mice.
• Probiotic pretreatment normalized both local (intestinal) and central (behavioral, hippocampal) parameters, irrespective of lymphocyte presence.
• These findings suggest probiotics benefit gut-brain-microbiota axis health by altering the microbiota.

Conclusions:

• Adaptive immune cells play a role in maintaining normal intestinal and brain health.
• Probiotics can effectively counteract immune-mediated deficits in the gut-brain-microbiota axis.
• Microbiota modulation by probiotics offers a therapeutic strategy for stress-related disorders affecting gut-brain communication.