When muscles weaken with age -- ScienceDaily
Working with our colleagues from the University of Aachen, we first systematically surveyed the changes taking place in the peripheral nerves of people aged between 65 and 79," Rudolf Martini describes his team's approach. During this, the researchers encountered an increased number of macrophages in the samples. Macrophages are cells of our body's immune system that engulf, digest and dispose microbes, foreign substances, cellular debris, aging cells etc. They set inflammatory responses in motion, help heal wounds and cleanse the tissue. Unfortunately, however, they also cause damage in some diseases.
To find out whether this also applies to age-related nerve degeneration, the scientists performed an experiment on mice. "For this purpose, we looked more closely at the nerves of 24-month-old mice which is an advanced age for mice," Rudolf Martini explains. It turned out that the age-related changes in the mice's peripheral nerves are very similar to those in humans. As in their human counterparts, the number of macrophages was increased in the mice. Also, the older animals had less strength than their younger siblings and their motor endplates, the synapses connecting nerves and muscle fibres, were also less intact.