Glass micro‐fibers: A model system for study of early events in myelination

Abstract

A system was developed to analyze early events in the process of myelination. Primary cultures of rat oligodendrocytes were maintained in the presence of glass micro-fibers which served as artificial axons. A culture chamber was constructed which allowed the close apposition of fibers and cells in a three-dimensional arrangement designed to resemble an in vivo environment. Cells cultured in the presence of glass micro-fibers coated with a glial cell matrix extract were induced to organize into clusters around the fibers. Examination of oligodendrocyte-fiber sandwiches by SEM revealed the presence of a number of cell contacts with the fibers. TEM images showed that, in most cases, fibers were surrounded by the cells and not multiply wrapped. Only occasionally was a loose wrapping of cell membrane observed around the fibers. Cells cultured in the presence of matrix-coated glass micro-fibers showed an increased production of sulfolipids that was at least partially dependent on the presence of the matrix coating. Coating of these "artificial axons" may aid in the identification of signal molecules produced by neurons which enable them to be myelinated.

A culture system to study oligodendrocyte myelination processes using engineered nanofibers

“…To this end, we have utilized electron-spinning technology to generate polystyrene nanofibers as an artificial scaffold for oligodendrocyte myelination 13, 14 . Previous studies utilizing either glass microfibers 15 and/or Vicryl nanofibers 16 obtained promising results with oligodendrocytes ensheathing and wrapping the fibers, however, the influence of fiber diameter was not examined. By engineering nanofibers with varying diameters (0.2 to 4.0 um), we demonstrate that fiber diameter is sufficient for initiating concentric wrapping by rat primary oligodendrocyte cultures.…”

Myelin plasticity, neural activity, and traumatic neural injury

“…Although these studies provide strong evidence both in vitro and in vivo for the importance of activity as a modifier of myelination, we must also consider in vitro work that shows OPCs differentiating and myelinating in the absence of axons. As early as 1990, cultures showed the initiation of wrapping on glass fibers (Bullock and Rome, ). Further work in vitro work showed the addition of factors deposited on the fibers affected myelination in culture (Howe, ).…”

Human oligodendrocytes in remyelination research

“…Various model systems have been developed for studying (re)myelination in vitro : cocultures of oligodendrocytes with dorsal root ganglion (DRG; Wang et al, ; Wood et al, ) or CNS neurons (Watkins et al, ), brain slice cultures from wild‐type and mutant mice (Billings‐Gagliardi et al, ; Zhang et al, ), or CNS spheroids (Vereyken et al, ). Oligodendrocytes were also shown to be able to enwrap artificial materials such as carbon (Althaus et al, ), glass (Bullock and Rome, ) and vicryl microfibers (Howe, ), polylactic acid nanofibers (Lee et al, ), or even paraformaldehyde‐fixed axons (Rosenberg et al, ) demonstrating that electrical activity of neurons, although beneficial, is not mandatory for myelination. While the vast majority of literature utilizing these models concerns rodent OPCs, also human oligodendrocytes have been tested for their myelination capacity in vitro in several studies listed in Table .…”