Biology Reference
In-Depth Information
Figure 3.4 Schematic drawing displaying the possible sites of action of ESWT in a reg-
enerating peripheral nerve and related cell bodies. In an untreated peripheral nerve,
regenerating neurites enter the vacated endoneural sheaths of the degenerated distal
peripheral nerve stump and grow along the aligned proliferating Schwann cells (bands
of Büngner), provided that the proximal and distal stumps are sufficiently close to each
other. It is suggested here that ESWT may improve the rate of axonal regeneration
through the activation of integrin molecules expressed on the axonal growth cones,
thereby promoting stronger binding to the various extracellular molecules, such as lam-
inin and fibronectin. The rate of proliferation of Schwann cells in the distal stump may
also increase, in conjunction with a more pronounced macrophage activity, which
results in the faster and more effective clearance of myelin debris. These actions may
have a cumulative effect on nerve regeneration, leading to a faster and more accurate
reinnervation process. The changes in the distal stump of the nerve and the more effec-
tive axonal regeneration is accompanied by molecular changes in the related cell
bodies, that is, upregulation of transcription factor ATF-3 and GAP-43. Apart from these
actions marked in red, it appears conceivable that many other molecular mechanisms
too are upregulated in order to support extensive axonal growth. The term endoneural
sheath refers to the fine network of reticular fibers and extracellular matrix molecules
around each myelinated axon as part of the endoneurium (ATF-3, activating transcrip-
tion factor-3; ECM, extracellular matrix; GAP-43, growth-associated phosphoprotein-43;
SW, shock waves).
without reactive cells, but surrounded by Schwann cells. Panel (C) presents a higher
magnification of the framed area in (B). Note the remyelinating Schwann cells (Sch)
and some collagen bundles (C) in the endoneurium. Scale bar in (A) and (B)
m,
in (C)
¼
1 mm. This figure is reproduced from the publication by
Hausner et al. (2012)
, with
the kind permission of Elsevier/Rightslink.
2
m
¼
