The present invention describes methods involving the use of muscle derived cells (MDCs), preferably obtained from skeletal muscle, to support the innervation and repair of damaged tissues and organs, particularly associated with nerve damage or neuropathy. The invention relates to MDCs for use in methods for promoting or enhancing innervation of nerve cells, particularly in the peripheral nervous system, and their ability to contribute to the development of neuronal tissue when MDCs are introduced at or near a tissue or organ site in need of repair due to injury, damage, disease, or dysfunction. Such methods arc useful for the treatment of central and peripheral nervous system disorders and to alleviate, abate, or eliminate the symptoms of neurologic or neurodegenerative diseases in animals, particularly mammals, including humans. The methods are also useful for treating both nerve and muscle tissue following injury, damage, or dysfunction to these tissue types.