Antibiotics save lives.
The bad news is they obliterate the good microbes in their wake which can lead to long-term immune and metabolic changes. And now researchers find that behavior and brain chemistry can also suffer.
Much evidence exists from both rodent and human studies showing microbial effect in brain and behavioral changes. Germ-free models have provided clues to these mechanisms.
Penicillin—the most widely used antibiotic in children– has lasting effects in both sexes in mouse models:
- Gut microbiota changes
- Increased cytokine expression in frontal cortex
- Blood-brain barrier integrity altered
- Behavior changes including impaired social behavior, aggression and anxiety
Researchers saw that low-dose penicillin in late pregnancy and early postnatal life induced long-term effects in the offspring of mice.
Probiotics may offset that.
In a novel new study with mouse models, a strain of lactobacillus rhamnosus was shown to prevent some of these changes.
Sophie Leclercq and colleagues in Brussels, Belgium reported their findings in April 2017 in Nature Communications : Low-dose penicillin in early life induces long-term changes in murine gut microbiota, brain cytokines and behavior.
- One group of mice received low doses of penicillin 1 week before pups’ birth and up until weaning.
- Second group received same doses of penicillin plus L. rhamnosus, 109 cfu. per day.
- Control group received food and water ad lib.
- Groups were then tested for various behaviors.
- Antibiotics decreased preference for social novelty (a sign of health); the probiotic prevented that effect.
- Antibiotics increased social aggression.
- Antibiotics induced major gut microbial changes in mice and offspring.
- Antibiotics increased expression of arginine vasopressin receptor 1B (Avpr1b)–involved in aggression in the frontal cortex.
- Cytokine changes in the frontal cortex of both sexes induced by antibiotics were partially prevented in the second female group which received probiotics.
Thus while we need antibiotics, we may be able to lessen potential negative long-term effects of early-life exposure with beneficial microbes.