I haven’t found any information showing that any mature skeletal muscle cells divide, but researching your question did teach me something about repair in skeletal muscles.

As you probably know, a skeletal muscle cell is one long strand made of 2 main proteins. It forms from a bunch of short single cells, which is why a mature skeletal muscle cell has many nuclei. Those immature cells are called myoblasts.

The mature muscle cell itself doesn’t divide, but some of those myoblasts hang around the mature muscle cells as satellite cells. If a muscle cell is damaged, those myoblasts “wake up” and start to divide. They can help to “patch” the damaged muscle. There’s a limit to how much they can fix, though.

Smooth muscle cells are attached to each other, but don’t become one long muscle. This may make it easier to have them divide. The smooth muscles of the uterus actually have to divide during pregnancy as the uterus grows a lot to accommodate the fetus, plus the placenta and amniotic sac.

All the sources I looked at say that cardiac muscles do not undergo mitosis once they are mature (so no division).

As you might imagine, there’s a lot of interest in figuring out what “switches off” the cell division in muscle cells so that maybe we can “switch on” the division in damaged muscle.One of the major themes of biology is the storage and transfer of information. This is a good example, so let’s take a closer look.

Genes carry information that codes for proteins. Some of the proteins are structural, like the keratin in our hair and nails. Some are enzymes, which catalyze (speed up) chemical reactions. Some are antibodies, which help fight disease. Some are signals, like the hormone insulin. Another group includes regulatory proteins. These switch other genes on and off. The regulatory genes are important in the development of an individual from a fertilized egg to whatever it becomes. As different regulatory genes switch on and off, they have a huge influence on a lot of other genes involved in how cells specialize and mature. Some researchers are working on potential therapies such as gene transfer to make mature muscle cells act more like immature muscle cells so that they will divide.

What might be some of the risks of a therapy that made a mature muscle cell act like an immature muscle cell?