Mature oligodendrocytes. Division following experimental demyelination in adult animals
L. S. Arenella and R. M. Herndon
Primary demyelination can be caused by injury to oligodendrocytes or to the
myelin sheaths that these cells maintain. Although remyelination does take
place in multiple sclerosis (MS), its possible role in the recovery from MS
attacks has been inadequately considered, partly because of the belief that
oligodendrocytes, once destroyed, cannot be replaced in the adult. The
injection of lysolecithin into the mouse spinal cord causes primary
demyelination, followed by the generation of new oligodendrocytes and
remyelination. By using a pulse label of tritiated thymidine, this
electron-microscopic autoradiographic study demonstrated a source of these
regenerated oligodendrocytes. The replacement of oligodendrocytes can occur
through the division of preexisting oligodendrocytes. This is the first
demonstration that mature oligodendrocytes are capable of dividing in older
animals. These results lend support to recent observations of an apparent
proliferation of these cells in an active MS lesion. We believe that the
ability of mature oligodendrocytes to divide and to remyelinate axons in
the adult may play an important role in the recovery from MS attacks.
