Structure and behavior of rat primary and secondary Schwann cells in vitro

Abstract

SUMMARYThe structure and motility of isolated rat primary (I) Schwann cells (SC) have been compared to that of subcultured (II) SC during and after mitotic stimulation. I SC contain myelin components which persist for 2 weeks in serum-free medium while they rapidly disappear in medium containing serum and high glucose concentration. These components were never detected in II SC. Both I SC and II SC after their mitotic phase are spindle-shaped, contain many intermediate and actin filaments, have no basement membrane but show intense migratory and undulatory activities. Rare fibroblasts in I cultures are recognized by their extremely variable shape, the presence of Thy 1.1 antigen in their membrane and their intense edge ruffling alternating with abrupt translocation. In contrast, I SC movements consist of intracellular translocation of nuclei along SC processes, which retract and extend constantly, and in slow rhythmic undulation episodes (2.3±0.2/min) alternating with migration at 135±50 µ/h. The total number of these episodes per day in serum-free medium is rigorously identical for different cells (166.3±0.2) and this uniformity of frequency suggests a genotypic basis. Cycles, consisting of an undulation episode followed by a resting interval, have mean durations of 8.6±4.1 min and a sharp peak of occurrence at 6 min, with exponential distribution of the longer periods. Motility of II SC is considerably inhibited during mitotic stimulation by cholera toxin and a pituitary extract while SC phenotype has changed to a flat multipolar cell with prominent Golgi and ribosomes. Migration is reduced to 24±2 µ/h and only 2 % of the SC show pulsations of the same periodicity as the I SC undulations. A dramatic increase in pulsation frequency occurs 6-12 h after removal of mitogenic factors when 80% of II SC start pulsating twice as fast for 2-3 days. When mitoses cease, SC quickly recover their SC phenotype with rhythmic undulations while migration speed increased to 92±20 µ/h. Thus, in spite of dramatic modification of shape, structure and behavior during mitotic stimulation, SC subsequently recover their unique motility pattern which might be essential for their myelinating function.Rat Schwann cells (SC), the myelin-form-ing cells of the peripheral nervous system, can now be cultured in isolation by using two different techniques [1][2][3]. In the first, rat dorsal root ganglia obtained just before birth are explanted and treated with antimitotic agents for a few days. After 10 days, the ganglia are excised and a "Schwann cell bed" is developed after the neurites are eliminated [1,2]. In the second technique, dissociation of newborn rat sciatic nerve results in a mixed population of SC and fibroblasts, which after 2 days of culturing are identified by their respective surface antigenic markers Ran 1 and Thy 1.1 [3,4]. In these cultures, fibroblast growth is first inhibited by AraC treatment and subsequently, by complement-mediated killing of Thy 1.1 positive cells [3]. SC growth can then be intensely stimulated by pi...

Cultured Peripheral Neuroglial Cells Are Highly Permissive to Sheep Prion Infection

“…Part of them exhibited a bi-or tripolar spindle shape, closely resembling that described for cultured Schwann cells (10,15). The others were comprised of cells that were more fusiform in shape.…”

In vivo and in vitro observations on laminin production by Schwann cells.

“…Schwann cells are often identified by their characteristic bipolar shape (39). It is our experience, however, that Schwann cells do not always exhibit this distinctive morphology.…”

Fibronectin promotes rat Schwann cell growth and motility.

“…Both fluorescein-and rhodamineconjugated second antibodies were obtained from N. L. Cappel Laboratories, Inc. (Cochranville, PA) and cholera toxin from Sigma Chemical Co. (St. Louis, MO). Pituitary factor was purified from bovine pituitary glands as described before (6,8).…”

“…properties both in vivo and in vitro (8,32). We have investigated the effect of exogenous fibronectin on the growth and migration of primary and secondary cultures of rat Schwann cells .…”