Study in mice suggests healthy microbiome is necessary for muscle growth

For muscles to grow following exercise, an in-tact microbiome was necessary in mice, according to new research published The Journal of Physiology.

For the study, the researchers let mice voluntarily exercise on running wheels every day for nine weeks with some mice administered antibiotics through their drinking water. The antibiotic treatment killed the bacteria of the gut microbiome. They then compared the muscles of healthy mice to the mice without an intact microbiome to see if the muscles adapted differently to wheel running.

The researchers found that the muscles of mice without an intact microbiome did not grow as much as the muscles of healthy mice, even though both groups of mice ran the same amount over the nine weeks of wheel running. These findings indicate a healthy gut microbiome is necessary for skeletal muscles to fully grow after exercising, the researchers said.

Although the researchers used a relatively low dose of antibiotics compared to previous studies, a limitation of the study is that they do not know if the antibiotics might have directly affected the ability of skeletal muscle to adapt to exercise. They also only used female mice in this initial study so they do not know if the findings will be the same in male mice. Finally, as with all animal studies, they do not know if the findings will translate into humans. 

The findings contribute to the growing body of evidence showing a connection between the gut microbiome and skeletal muscles. The findings suggest the gut microbiome makes substances that help skeletal muscles to become larger after exercising.