scholarly journals Morphometric and ultrastructural changes with ageing in mouse peripheral nerve

1999 ◽  
Vol 195 (4) ◽  
pp. 563-576
Author(s):  
DOLORES CEBALLOS ◽  
JORDI CUADRAS ◽  
ENRIQUE VERDÚ ◽  
XAVIER NAVARRO
Keyword(s):  
Peripheral Nerve ◽  
Morphological Changes ◽  
Quantitative Information ◽  
Unmyelinated Axon ◽  
Ultrastructural Changes ◽  
Myelinated Fibre ◽  
Nerve Fibres ◽  
Internodal Length ◽  
Myelinated Fibres ◽  
Ageing Period

Qualitative and quantitative information is reported on the morphological changes that occur in nerve fibres and nonneuronal cells of peripheral nerve during the lifetime of the mouse. Tibial nerves of mice aged 6–33 mo were studied. With ageing, collagen accumulates in the perineurium and lipid droplets in the perineurial cells. Macrophages and mast cells increase in number, and onion bulbs and collagen pockets are frequently present. Schwann cells associated with myelinated fibres (MF) slightly decrease in number in parallel with an increase of the internodal length from 6 to 12 mo, but increase in older nerves when demyelination and remyelination are common. The unmyelinated axon to myelinated fibre (UA/MF) ratio was about 2 until 12 mo, decreasing to 1.6 by 27 mo. In older mice, the loss of nerve fibres involves UA (50% loss of 27–33 mo cf. 6 mo) more markedly than MF (35%). In aged nerves wide incisures and infolded or outfolded myelin loops are frequent, resulting in an increased irregularity in the morphology of fibres along the internodes. In the mouse there is an adult time period, 12–20 mo, during which several features of degeneration progressively appear, and an ageing period from 20 mo upwards when the nerve suffers a general disorganisation and marked fibre loss.

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.

scholarly journals A Novel Model of Cancer-Induced Peripheral Neuropathy and the Role of TRPA1 in Pain Transduction

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Ahmad Maqboul ◽  
Bakheet Elsadek
Keyword(s):  
Immune Cells ◽  
Peripheral Nerves ◽  
Morphological Changes ◽  
Nerve Fibres ◽  
Cold Allodynia ◽  
Sciatic Nerves ◽  
Pain Transduction ◽  
Thermal Stimuli ◽  
Novel Model

Background. Models of cancer-induced neuropathy are designed by injecting cancer cells near the peripheral nerves. The interference of tissue-resident immune cells does not allow a direct contact with nerve fibres which affects the tumor microenvironment and the invasion process. Methods. Anaplastic tumor-1 (AT-1) cells were inoculated within the sciatic nerves (SNs) of male Copenhagen rats. Lumbar dorsal root ganglia (DRGs) and the SNs were collected on days 3, 7, 14, and 21. SN tissues were examined for morphological changes and DRG tissues for immunofluorescence, electrophoretic tendency, and mRNA quantification. Hypersensitivities to cold, mechanical, and thermal stimuli were determined. HC-030031, a selective TRPA1 antagonist, was used to treat cold allodynia. Results. Nociception thresholds were identified on day 6. Immunofluorescent micrographs showed overexpression of TRPA1 on days 7 and 14 and of CGRP on day 14 until day 21. Both TRPA1 and CGRP were coexpressed on the same cells. Immunoblots exhibited an increase in TRPA1 expression on day 14. TRPA1 mRNA underwent an increase on day 7 (normalized to 18S). Injection of HC-030031 transiently reversed the cold allodynia. Conclusion. A novel and a promising model of cancer-induced neuropathy was established, and the role of TRPA1 and CGRP in pain transduction was examined.

scholarly journals Characterisation of Morphology in Musculus Semitendinosus Tendon Used for Anterior Cruciate Ligament Reconstruction: A Pilot Study

2020 ◽  
Vol 18 (1) ◽  
pp. 1-6
Author(s):  
Janis Davis Osipovs ◽  
Mara Pilmane ◽  
Modris Ciems
Keyword(s):  
Anterior Cruciate Ligament ◽  
Morphological Changes ◽  
Cruciate Ligament ◽  
Collagen I ◽  
Collagen Fibres ◽  
Nerve Fibres ◽  
Tissue Ischemia ◽  
Moderate Number ◽  
Collagen Iii ◽  
Anterior Cruciate

SummaryIntroductionAnterior cruciate ligament (ACL) rupture is very common in athletes. In the general population, incidence is approximately 33 per 100 000 people.Aim of the studyThe aim of the study was the evaluation of morphological changes in the musculus semitendinosus tendon used for the reconstruction of ACL to understand the quality of most common for surgery used material.Material and methodsThe materials were obtained from four ACL autologous hamstring reconstruction surgeries. The tissue was stained with hematoxyllin and eosin and with immunohistochemical (IMH) staining of PGP9.5, VEGF, collagen I and collagen III. The material was evaluated with semiquantitative method.ResultsRoutine staining showed practically unchanged tendon structure, with one exception when sclerotic blood vessels were observed in endotenon. Collagen III IMH demonstrated moderate to numerous positive collagen fibres in two cases, but in other two there were only few positive structures seen. Collagen I IMH showed few to moderate number of positive collagen fibres in all cases. In two cases, moderate number of PGP9.5 positive nerve fibres was observed and in two other cases occasional to few number of positive structures was detected. PGP 9.5 marked higher number of nerve fibres in peritenon than in endotenon. Numerous VEGF positive endotheliocytes were observed in two cases, but in two other cases VEGF positive endotheliocytes were occasional.ConclusionsTendon of musculus semitendinosus displays two patterns of distribution of tissue ischemia, neuropeptide containing innervation and collagen I and III. Collagen III is thought to be evaluated as a response of tendon to the ischemia and intensive innervation, while increase of collagen I probably is related to the relatively unchanged vascularity and innervation. The pattern of musculus semitendinosus tendon structural changes seems to be connected to the individual homeostasis in patients persisting before the usage of tendon for the reconstruction.

Effect of vinblastine and cytochalasin B on the cytoskeletal domains in 3T3 cells

1981 ◽  
Vol 48 (1) ◽  
pp. 55-73
Author(s):  
J.H. Temmink ◽  
H. Spiele
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Cytochalasin B ◽  
Morphological Changes ◽  
Ultrastructural Changes ◽  
3T3 Cells ◽  
Cytoplasmic Material ◽  
Transmission Electron ◽  
Cytoskeletal Elements ◽  
Scanning Electron

Normal 3T3 cells were exposed to vinblastine and cytochalasin B in an attempt to correlate the morphological changes of the cell surface as seen in the scanning electron microscope with ultrastructural changes of the cytoskeletal elements as seen in critical-point-dried cells in the transmission electron microscope. Special attention was given to the changes in the cytoplasmic domains distinguished in a previous paper. Cytochalasin B primarily affects the ultrastructure of the cytocortical domain by inducing the formation of condensation foci on the cytoplasmic material. Vinblastine not only induces the depolymerization of microtubules and the perinuclear concentration of intermediate filaments, but it also causes the disappearance of stress fibres from the cortical cytoplasm and the widening of the cytocortex at the expense of the endoplasmic domain. These results support the hypothesis that the differentiation in ultrastructural domains is dependent on the spreading of the cells and their adhesion to substrate.

scholarly journals Modulation of Metamorphic and Regenerative Events by Cold Atmospheric Pressure Plasma Exposure in Tadpoles, Xenopus laevis

2019 ◽  
Vol 9 (14) ◽  
pp. 2860 ◽  
Author(s):  
Ma Veronica Holganza ◽  
Adonis Rivie ◽  
Kevin Martus ◽  
Jaishri Menon
Keyword(s):  
Atmospheric Pressure ◽  
Developmental Plasticity ◽  
Morphological Changes ◽  
Atmospheric Pressure Plasma ◽  
Ultrastructural Changes ◽  
Plasma Exposure ◽  
Tail Regeneration ◽  
Developmental Processes ◽  
Pressure Plasma ◽  
Metamorphic Development

Atmospheric pressure plasma has found wide clinical applications including wound healing, tissue regeneration, sterilization, and cancer treatment. Here, we have investigated its effect on developmental processes like metamorphosis and tail regeneration in tadpoles. Plasma exposure hastens the process of tail regeneration but delays metamorphic development. The observed differences in these two developmental processes following plasma exposure are indicative of physiological costs associated with developmental plasticity for their survival. Ultrastructural changes in epidermis and mitochondria in response to the stress of tail amputation and plasma exposure show characteristics of cellular hypoxia and oxidative stress. Mitochondria show morphological changes such as swelling with wide and fewer cristae and seem to undergo processes such as fission and fusion. Complex interactions between calcium, peroxisomes, mitochondria and their pore transition pathways are responsible for changes in mitochondrial structure and function, suggesting the subcellular site of action of plasma in this system.

scholarly journals Deep learning-enabled analysis reveals distinct neuronal phenotypes induced by aging and cold-shock

BMC Biology ◽  
2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Sahand Saberi-Bosari ◽  
Kevin B. Flores ◽  
Adriana San-Miguel
Keyword(s):  
Deep Learning ◽  
Cold Shock ◽  
Morphological Changes ◽  
Quantitative Information ◽  
Qualitative Assessment ◽  
Morphological Alteration ◽  
Phenotypic Profile ◽  
C Elegans ◽  
Unbiased Manner ◽  
Neural Network Algorithm

Abstract Background Access to quantitative information is crucial to obtain a deeper understanding of biological systems. In addition to being low-throughput, traditional image-based analysis is mostly limited to error-prone qualitative or semi-quantitative assessment of phenotypes, particularly for complex subcellular morphologies. The PVD neuron in Caenorhabditis elegans, which is responsible for harsh touch and thermosensation, undergoes structural degeneration as nematodes age characterized by the appearance of dendritic protrusions. Analysis of these neurodegenerative patterns is labor-intensive and limited to qualitative assessment. Results In this work, we apply deep learning to perform quantitative image-based analysis of complex neurodegeneration patterns exhibited by the PVD neuron in C. elegans. We apply a convolutional neural network algorithm (Mask R-CNN) to identify neurodegenerative subcellular protrusions that appear after cold-shock or as a result of aging. A multiparametric phenotypic profile captures the unique morphological changes induced by each perturbation. We identify that acute cold-shock-induced neurodegeneration is reversible and depends on rearing temperature and, importantly, that aging and cold-shock induce distinct neuronal beading patterns. Conclusion The results of this work indicate that implementing deep learning for challenging image segmentation of PVD neurodegeneration enables quantitatively tracking subtle morphological changes in an unbiased manner. This analysis revealed that distinct patterns of morphological alteration are induced by aging and cold-shock, suggesting different mechanisms at play. This approach can be used to identify the molecular components involved in orchestrating neurodegeneration and to characterize the effect of other stressors on PVD degeneration.

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