Biomedical Engineering Reference
In-Depth Information
Fig. 6.2
Structures of
physiological endoneurium
and perineurium. (
To p
; a):
Diagram suggesting the main
features of the endoneurial
stroma surrounding nerve
fibers. Each nerve fiber (
NF
)
is embedded in a matrix
composed of fluid, collagen
fibers of the endoneurial
stroma, and cells forming the
endoneurial microenviron-
ment. The inner surface of
the perineurium is shown on
the
left
. (From Olsson 1990)
(
Bottom
; b): Cross sectional
view of the perineurium (
pn.
)
of rat sural nerve. Collagen
fibers comprising the epineu-
rium (
ep.
) and endoneurium
(
en.
) are also shown. Bar:
1 µm. (From Thomas and
Jones 1967)
6.2.2
Synthetic Pathways to Myelinated Axons and Basement
Membrane
Myelinated axons with their associated BM have been synthesized both in vitro and
in vivo.
Explanted neurons providing an outgrowth of axons have been a basic compo-
nent used in the studies of synthesis of myelinated axons in vitro (Bunge and Bunge
1978). Explants have been established in culture using various media, including
human placental serum, and have been treated with anti-mitotic agents to eliminate
nonneuronal cells (Obremski and Bunge 1995). Axonal processes (neurites) have
grown radially from the explant, serving as the source of axons for the experimental
protocol. SCs can be obtained from another explanted neuron, purified, dissociated,
and cultured in media such as fetal calf serum or a defined medium before addition
to the neuron culture under study. A neuron such as the sensory dorsal root ganglion
stimulates synthesis of a myelin sheath around its neurites and is, therefore, useful
