Microflora and brain

Study: Antibiotics have a devastating effect on the brain

Elena Subbotina, Rossiyskaya Gazeta

Treatment involving long-term use of antibiotics may negatively affect brain function and the formation of new brain cells, scientists from the Max Delbruck Center for Molecular Medicine in Germany suggested (see the press release Healthy intestinal flora keeps the mind sharp – with some help from the immune system – VM).

The study talks about the role of special immune cells that serve as an intermediary between intestinal bacteria and the brain. Actually, the intestines and the brain "communicate" with each other through hormones, metabolic products or direct neural connections. But a specific population of immune cells – monocytes – works as an additional link between them.

Scientists conducted experiments on mice. Using a strong mixture of antibiotics, they "turned off" the intestinal microbiome in rodents.

It turned out that in the hippocampus of such animals, much fewer nerve cells were subsequently formed compared to mice from the control group who were not treated with antibiotics.

New neurons in the hippocampus of mice are marked in red:
"treated" with antibiotics (left) and from the control group (right) – VM.

The formation of new brain cells is known as neurogenesis. It is of great importance for certain memory functions. Its decline is also associated with the very deterioration of memory observed in rodents from the group of antibiotics.

Along with the violation of neurogenesis after the "shutdown" of the microbiome, there was also a significant reduction in the population of specific immune cells in the brain – Ly6C^(hi) monocytes. Observations have shown that when these cells were removed from the body, the neurogenesis process worsened, and when injected, on the contrary, it was restored.

Diagram from the article Mohle et al. Ly6Chi Monocytes Provide a Link between Antibiotic-Induced Changes in Gut Microbiota and Adult Hippocampal Neurogenesis (Cell Reports, 2016) – WM.

Mice from the antibiotic group were treated using two different strategies – rodents were either given a mixture of certain types of bacteria, or allowed to train on a treadmill, thereby reversing the negative effects of antibiotic treatment.

The number of monocytes has increased, and memory work and the process of neurogenesis have improved. At the same time, an attempt to restore immune and brain functions with the help of microbiota taken from mice from the control group failed.

Portal "Eternal youth" http://vechnayamolodost.ru  24.05.2016