Experiments have shown that mice with no gut microbes show differences in how much they move and in their anxiety-like behavior than mice with normal gut bacteria. Mice treated with "probiotic" Lactobacillus bacteria showed a different gene expression in the brain, reduced anxiety behavior and stress hormone levels than untreated mice.
The effects may extend to diseases that are seemingly unrelated to the digestive system. In the work published today, researchers studied mice bred to develop a disease similar to multiple sclerosis.
Those raised in an environment with no bacteria never developed symptoms. Once typical gut bacteria were introduced, the mice began to show signs of the disease.
"I think what our study really shows is the importance of the gut microbiota in the initial phase of the disease," said Gurumoorthy Krishnamoorthy of the Max Planck Institute of Immunobiology and Epigenetics in Freiburg, Germany who led the study with colleague Hartmut Wekerle.
Of course, it's impossible for humans to live a microbe-free lifestyle, but the findings suggest the microbial community may play a role in human multiple sclerosis. The team will now look for specific microbes that may be responsible for triggering symptoms.
http://news.discovery.com/human/gut-bacteria-obesity-111026.html