The Distribution of Electron-Dense Tracers in Peripheral Nerve Fibres

1971 ◽  
Vol 8 (2) ◽  
pp. 541-555
Author(s):  
SUSAN M. HALL ◽  
P. L. WILLIAMS
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Myelin Sheath ◽  
External Surface ◽  
Nerve Fibres ◽  
Cell Cytoplasm ◽  
Line Region ◽  
Periaxonal Space

Two electron-dense tracers, ferritin and lanthanum, have been administered to peripheral nerve fibres, and their uptake has been studied ultrastructurally. It was found that the perineurium was an effective barrier to ferritin in vivo, and the tracer was subsequently injected sub-perineurially. Ferritin uptake over a 120-min period was confined to occasional phagocytic vesicles in perineurial and Schwann cells, and to the nodal gap substance and paranodal periaxonal space. No uptake was observed in the myelin sheath, incisural intraperiod line gap, or in the axoplasm. Soaking fibres in ferritin in vitro resulted in a more generalized cytoplasmic and axoplasmic uptake, although the myelin sheath and Schmidt-Lanterman incisures remained devoid of the tracer. Lanthanum nitrate, included in the fixative solution, delineated the patent incisural intraperiod line gap, and outlined the external surface of the terminal loops of nodal Schwann cell cytoplasm, and the paranodal Schwann cell-axolemmal junction. Unlike ferritin, La3+ penetrated the myelin sheath, being usually confined to the intraperiod line region of the outer lamellae, where it was associated with a widening of the lamellar unit, and an apparent splitting of the intraperiod line. The results are discussed with regard to distribution of extracellular space in peripheral nerve fibres.

The in Vivo and Ultrastructural Effects of Injection of Lysophosphatidyl Choline into Myelinated Peripheral Nerve Fibres of the Adult Mouse

1971 ◽  
Vol 9 (3) ◽  
pp. 769-789
Author(s):  
SUSAN M. HALL ◽  
N. A. GREGSON
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Myelin Sheath ◽  
Time Course ◽  
Adult Mouse ◽  
Phospholipase A ◽  
Nerve Fibres ◽  
Lysophosphatidyl Choline

The action of phospholipase A and lysophosphatidyl choline (LPC) on mature, myelinated peripheral nerve fibres has been studied in vivo and electron microscopically, following sub-perineurial injection of these substances. Within 30 min, demyelination was observed in vivo along cylindrico-conical segments, spreading from Schmidt-Lanterman incisures and nodes of Ranvier. By 96 h, all traces of the myelin sheath had disappeared from the area of the lesion, and had been replaced by debris-laden cells lying in chains parallel to one another and the long axis of the fibre. During the next few weeks these cells gradually disappeared, and numerous finely myelinated axons, running between, and in continuity with, the normal fibres proximal and distal to the lesion were observed. If lower concentrations of LPC were used the number of fibres involved decreased, although the demyelinative changes followed the same time-course. Ultrastructurally, demyelination involved progressive disruption and removal of the lamellar sheath, observed initially as a splitting of the intraperiod line within 30 min. Subsequent breakdown resulted in the formation of strands of 4-6 nm repeat material which was further degraded through quintuple- and triple-layered lamellar units to foam-like systems of disorganized lamellar fragments. The Schwann cell and axons appeared to be undamaged by phospholipase A and LPC, and retained their normal impermeability to exogenous ferritin. The significance of the demyelinating capacity of LPC in vivo is discussed in terms of its known action on myelin in vitro, the rapidity and apparent specificity of its action demonstrated in this study, and its potential involvement in pathological demyelination.

scholarly journals A TIME-SEQUENCE AUTORADIOGRAPHIC STUDY OF THE IN VIVO INCORPORATION OF [1, 2-3H]CHOLESTEROL INTO PERIPHERAL NERVE MYELIN

1973 ◽  
Vol 58 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Frank A. Rawlins
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Myelin Sheath ◽  
Central Zone ◽  
Autoradiographic Study ◽  
Nerve Fibers ◽  
Time Sequence ◽  
Time Interval ◽  
Electron Microscope Autoradiography

A time-sequence study of the incorporation and distribution of cholesterol in peripheral nerve myelin was carried out by electron microscope autoradiography. [1,2-3H]Cholesterol was injected into 10-day old mice and the sciatic nerves were dissected out at 10, 20, 40, 60, 90, 120, and 180 min after the injection. 20 min after injection the higher densities of grains due to the presence of [3H]cholesterol were confined to the outer and inner edges of the myelin sheath. Practically no cholesterol was detected in the midzone of the myelin sheath. 1 ½ h after injection, cholesterol showed a wider distribution within the myelin sheath, the higher densities of grains occurring over the two peripheral myelin bands, each approximately 3,100 Å wide. Cholesterol was also present in the center of the myelin sheath but to a considerably lesser extent. 3 h after injection cholesterol appeared homogeneously distributed within the myelin sheath. Schwann cell and axon compartments were also labeled at each time interval studied beginning 20 min postinjection. These observations indicate that preformed cholesterol enters myelin first and almost simultaneously through the inner and outer edges of the sheath; only after 90 min does the density of labeled cholesterol in the central zone of myelin reach the same density as that in the outer and inner zones. These findings suggest that cholesterol used by the nerve fibers in the formation and maintenance of the myelin sheath enters the lamellae from the Schwann cell cytoplasm and from the axon. The possibility of a bidirectional movement of molecules, i.e. from the Schwann cell to the axon and from the axon to the Schwann cell through the myelin sheath, is noted. The results are discussed in the light of recent observations on the exchange, reutilization, and transaxonal movement of cholesterol.

scholarly journals Human Hair Derived Keratins Mediate Schwann Cell Behavior in vitro and Facilitate Rapid Peripheral Nerve Regeneration in vivo

2007 ◽  
Vol 21 (6) ◽  
Author(s):  
Paulina Sierpinski ◽  
Jeffrey Garrett ◽  
Jianjun Ma ◽  
Peter Apel ◽  
Tom Smith ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Human Hair ◽  
Peripheral Nerve Regeneration ◽  
Cell Behavior

The Fine Structure and Morphological Organization of the Peripheral Nerve-fibres and Trunks of the Cockroach (Periplaneta americana)

1958 ◽  
Vol s3-99 (47) ◽  
pp. 333-340
Author(s):  
ARTHUR HESS
Keyword(s):  
Cell Membrane ◽  
Schwann Cell ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Myelin Sheath ◽  
Plasma Membranes ◽  
Periplaneta Americana ◽  
Nerve Trunk ◽  
Bromphenol Blue ◽  
Nerve Fibres

Sections of the peripheral nerve-trunks of the metathoracic leg of the cockroach (Periplaneta americana) were studied with the electron microscope. Paraffin sections were also prepared and stained. Protargol succeeds in staining the nerve-fibres. Osmium tetroxide, a modified Weigert procedure, and Luxol fast blue stain the myelin sheaths, as does mercuric bromphenol blue, a protein stain. The axoplasm is relatively free of formed elements; it contains mitochondria. The myelin sheath, when present on the largest and also some smaller fibres, consists of about two or three loose over lapping processes of Schwann cells, covered by their plasma membranes, enclosing lipid-like droplets and having a beaded appearance. Between the nerve-fibres in the nerve-trunk is Schwann-cell cytoplasm, which arises from Schwann cells that surround the whole nerve-trunk. The same fold of Schwann-cell membrane may enter into the formation of the myelin sheath around more than one nerve-fibre. Several small non-myelinated fibres, which may be as small as 0.3 µ in diameter or less, may be enclosed in the same fold of Schwann-cell membrane. Outside of the Schwann-cell layer and surrounding the nerve-trunk is a thin layer of connective tissue, which does not send trabeculae into the interior of the nerve. Tracheae and tracheoles accompany the nerve but are not included within the sheaths surrounding a nerve-trunk, even near the termination of the nerve-fibres in muscle. The structure of the cockroach peripheral nerve is compared with that described by previous investigators, with that of other insects, and with invertebrate and vertebrate nerve.

The fine structure and morphological organization of non-myelinated nerve fibres

1956 ◽  
Vol 144 (917) ◽  
pp. 496-506 ◽  
Keyword(s):  
Fine Structure ◽  
Schwann Cell ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Myelin Sheath ◽  
Peripheral Nerves ◽  
Nerve Fibres ◽  
Myelinated Nerve ◽  
Morphological Organization ◽  
Myelinated Fibres

The fine structure and morphological organization of non-myelinated nerve fibres were studied by ultra-thin sectioning and electron microscopy in peripheral nerves, autonomic nerves and dorsal roots. Several non-myelinated fibres share the cytoplasm of a Schwann cell. The Schwann cells of non-myelinated fibres form a syncytium. The fibres are incompletely sur­rounded by Schwann cell cytoplasm and are suspended in the cytoplasm by mesaxons formed by the plasma membranes of the Schwann cell. The various relationships of mesaxon and nerve fibre are described. Non-myelinated fibres which do not share a Schwann cell are seen very frequently in the sciatic nerve of a new-born mouse but become less common as myelination proceeds and are rare in adults. It is therefore suggested that in developing peripheral nerves, the non­ myelinated fibres that are destined to myelinate are not organized into groups within a single Schwann cell, even before their myelin sheath has appeared; they are, at least for the ages examined here, individuals in relation to a surrounding individual Schwann cell. It is also suggested that the non-myelinated fibres that will never acquire a myelin sheath are organized in a developing peripheral nerve in the same manner as in the adult nerve—several fibres sharing a single Schwann cell that is part of a syncytial system of Schwann cells. Thus, in a developing peripheral nerve, it appears that two types of non-myelinated fibres are present—one destined to myelinate and lying alone in its own Schwann cell and the other, destined to remain unmyelinated and sharing, along with other non-myelinated fibres of the same type, a Schwann cell. The significance of these observations is discussed in relation to the development of nerve fibres and possible physiological importance.

Diploid and hyperdiploid rat Schwann cell strains displaying negative autoregulation of growth in vitro and myelin sheath-formation in vivo

1994 ◽  
Vol 52 (2) ◽  
pp. 119-127 ◽  
Author(s):  
Laurence W. Haynes ◽  
James A. Rushton ◽  
Matthew F. Perrins ◽  
Jason K. Dyer ◽  
Rosemary Jones ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Myelin Sheath ◽  
Sheath Formation ◽  
Cell Strains ◽  
Negative Autoregulation

scholarly journals Interleukin-4 Regulates the Expression of CD209 and Subsequent Uptake of Mycobacterium leprae by Schwann Cells in Human Leprosy

2010 ◽  
Vol 78 (11) ◽  
pp. 4634-4643 ◽  
Author(s):  
Rosane M. B. Teles ◽  
Stephan R. Krutzik ◽  
Maria T. Ochoa ◽  
Rosane B. Oliveira ◽  
Euzenir N. Sarno ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Primary Cultures ◽  
Mycobacterium Leprae ◽  
Microbial Pathogens ◽  
Interleukin 4 ◽  
Common Mechanism ◽  
Specific Cell

ABSTRACT The ability of microbial pathogens to target specific cell types is a key aspect of the pathogenesis of infectious disease. Mycobacterium leprae, by infecting Schwann cells, contributes to nerve injury in patients with leprosy. Here, we investigated mechanisms of host-pathogen interaction in the peripheral nerve lesions of leprosy. We found that the expression of the C-type lectin, CD209, known to be expressed on tissue macrophages and to mediate the uptake of M. leprae, was present on Schwann cells, colocalizing with the Schwann cell marker, CNPase (2′,3′-cyclic nucleotide 3′-phosphodiesterase), along with the M. leprae antigen PGL-1 in the peripheral nerve biopsy specimens. In vitro, human CD209-positive Schwann cells, both from primary cultures and a long-term line, have a higher binding of M. leprae compared to CD209-negative Schwann cells. Interleukin-4, known to be expressed in skin lesions from multibacillary patients, increased CD209 expression on human Schwann cells and subsequent Schwann cell binding to M. leprae, whereas Th1 cytokines did not induce CD209 expression on these cells. Therefore, the regulated expression of CD209 represents a common mechanism by which Schwann cells and macrophages bind and take up M. leprae, contributing to the pathogenesis of leprosy.

Chitin conduits modified with DNA-peptide coating promote the peripheral nerve regeneration

2021 ◽  
Author(s):  
Songyang Liu ◽  
Liping Zhou ◽  
Ci Li ◽  
Tiantian Min ◽  
Changfeng Lu ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Amide Bond ◽  
Primary Amines ◽  
Direct Reaction ◽  
Ct Dna ◽  
Peptide Coating

Abstract Peripheral nerve injury (PNI) is one of the common clinical injuries which needs to be addressed. Previous studies demonstrated the effectiveness of using biodegradable chitin (CT) conduits small gap tubulization technology as a substitute for traditional epineurial neurorrhaphy. Aiming to improve the effectiveness of CT conduits in repairing PNI, we modified their surface with a DNA-peptide coating. The coating consisted of single strand DNA (ssDNA) and its complementary DNA’-peptide mimics. First, we immobilize ssDNA (DNA1+2) on CT conduits by EDC/NHS method to construct CT/DNA conduits. EDC/NHS was used to activate carboxyl groups of modified ssDNA for direct reaction with primary amines on the chitin via amide bond formation. Then, DNA1’-BDNF+DNA2’-VEGF mimic peptide （RGI+KLT）were bonded to CT/DNA conduits by complementary base pairing principle at room temperature to form CT/RGI+KLT conduits. When the surrounding environment rose to a certain point (37℃), the CT/RGI+KLT conduits achieved sustainable release of DNA’-peptide. In vitro, the CT conduits modified with the DNA-peptide coating promoted the proliferation and secretion of Schwann cells by maintaining their repair state. It also promoted the proliferation of HUVECs and axon outgrowth of DRG explants. In vivo, CT/RGI+KLT conduits promoted regeneration of injured nerves and functional recovery of target muscles, which was facilitated by the synergistic contribution of angiogenesis and neurogenesis. Our research brings DNA and DNA-peptide hybrids into the realm of tissue engineering to repair peripheral nerve injury.

scholarly journals N-Cadherin Upregulation Promotes the Neurogenic Differentiation of Menstrual Blood-Derived Endometrial Stem Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yanli Liu ◽  
Fen Yang ◽  
Shengying Liang ◽  
Qing Liu ◽  
Sulei Fu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Peripheral Nerve ◽  
Therapeutic Option ◽  
In Vivo Studies ◽  
Menstrual Blood ◽  
Neurogenic Differentiation ◽  
Endometrial Stem Cells ◽  
Medical Disorders

Peripheral nerve injuries are typically caused by either trauma or medical disorders, and recently, stem cell-based therapies have provided a promising treatment approach. Menstrual blood-derived endometrial stem cells (MenSCs) are considered an ideal therapeutic option for peripheral nerve repair due to a noninvasive collection procedure and their high proliferation rate and immunological tolerance. Here, we successfully isolated MenSCs and examined their biological characteristics including their morphology, multipotency, and immunophenotype. Subsequent in vitro studies demonstrated that MenSCs express high levels of neurotrophic factors, such as NT3, NT4, BDNF, and NGF, and are capable of transdifferentiating into glial-like cells under conventional induction conditions. Moreover, upregulation of N-cadherin (N-cad) mRNA and protein expression was observed after neurogenic differentiation. In vivo studies clearly showed that N-cad knockdown via in utero electroporation perturbed the migration and maturation of mouse neural precursor cells (NPCs). Finally, a further transfection assay also confirmed that N-cad upregulation in MenSCs results in the expression of S100. Collectively, our results confirmed the paracrine effect of MenSCs on neuroprotection as well as their potential for transdifferentiation into glial-like cells and demonstrated that N-cad upregulation promotes the neurogenic differentiation of MenSCs, thereby providing support for transgenic MenSC-based therapy for peripheral nerve injury.

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