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Maniglier M, Vidal M, Bachelin C, Deboux C, Chazot J, Garcia-Diaz B, Baron-Van Evercooren A. Satellite glia of the adult dorsal root ganglia harbor stem cells that yield glia under physiological conditions and neurons in response to injury. Stem Cell Reports 2022; 17:2467-2483. [PMID: 36351367 PMCID: PMC9669640 DOI: 10.1016/j.stemcr.2022.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/03/2022] [Accepted: 10/04/2022] [Indexed: 11/09/2022] Open
Abstract
The presence of putative stem/progenitor cells has been suggested in adult peripheral nervous system (PNS) tissue, including the dorsal root ganglion (DRG). To date, their identification and fate in pathophysiological conditions have not been addressed. Combining multiple in vitro and in vivo approaches, we identified the presence of stem cells in the adult DRG satellite glial population, and progenitors were present in the DRGs and sciatic nerve. Cell-specific transgenic mouse lines highlighted the proliferative potential of DRG stem cells and progenitors in vitro. DRG stem cells had gliogenic and neurogenic potentials, whereas progenitors were essentially gliogenic. Lineage tracing showed that, under physiological conditions, adult DRG stem cells maintained DRG homeostasis by supplying satellite glia. Under pathological conditions, adult DRG stem cells replaced DRG neurons lost to injury in addition of renewing the satellite glial pool. These novel findings open new avenues for development of therapeutic strategies targeting DRG stem cells for PNS disorders. Adult murine DRGs contain slowly proliferating putative stem cells The putative stem cells are a subpopulation of adult DRG satellite cells Purified adult DRG putative stem cells generate neurons and glia in vitro They are gliogenic in vivo and generate neurons in response to injury
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Mermet-Joret N, Chatila N, Pereira B, Monconduit L, Dallel R, Antri M. Lamina specific postnatal development of PKCγ interneurons within the rat medullary dorsal horn. Dev Neurobiol 2016; 77:102-119. [PMID: 27346325 DOI: 10.1002/dneu.22414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/21/2016] [Accepted: 06/22/2016] [Indexed: 01/17/2023]
Abstract
Protein kinase C gamma (PKCγ) interneurons, located in the superficial spinal (SDH) and medullary dorsal horns (MDH), have been shown to play a critical role in cutaneous mechanical hypersensitivity. However, a thorough characterization of their development in the MDH is lacking. Here, it is shown that the number of PKCγ-ir interneurons changes from postnatal day 3 (P3) to P60 (adult) and such developmental changes differ according to laminae. PKCγ-ir interneurons are already present at P3-5 in laminae I, IIo, and III. In lamina III, they then decrease from P11-P15 to P60. Interestingly, PKCγ-ir interneurons appear only at P6 in lamina IIi, and they conversely increase to reach adult levels at P11-15. Analysis of neurogenesis using bromodeoxyuridine (BrdU) does not detect any PKCγ-BrdU double-labeling in lamina IIi. Quantification of the neuronal marker, NeuN, reveals a sharp neuronal decline (∼50%) within all superficial MDH laminae during early development (P3-15), suggesting that developmental changes in PKCγ-ir interneurons are independent from those of other neurons. Finally, neonatal capsaicin treatment, which produces a permanent loss of most unmyelinated afferent fibers, has no effect on the development of PKCγ-ir interneurons. Together, the results show that: (i) the expression of PKCγ-ir interneurons in MDH is developmentally regulated with a critical period at P11-P15, (ii) PKCγ-ir interneurons are developmentally heterogeneous, (iii) lamina IIi PKCγ-ir interneurons appear less vulnerable to cell death, and (iv) postnatal maturation of PKCγ-ir interneurons is due to neither neurogenesis, nor neuronal migration, and is independent of C-fiber development. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 102-119, 2017.
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Affiliation(s)
- Noemie Mermet-Joret
- Neuro-Dol, Clermont Université, Université D'Auvergne, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107, Clermont-Ferrand, F-63100, France
| | - Nadwa Chatila
- Neuro-Dol, Clermont Université, Université D'Auvergne, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107, Clermont-Ferrand, F-63100, France
| | - Bruno Pereira
- Biostatistics Unit (DRCI), CHU Clermont-Ferrand, Clermont-Ferrand, F-63100, France
| | - Lénaic Monconduit
- Neuro-Dol, Clermont Université, Université D'Auvergne, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107, Clermont-Ferrand, F-63100, France
| | - Radhouane Dallel
- Neuro-Dol, Clermont Université, Université D'Auvergne, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107, Clermont-Ferrand, F-63100, France.,Service D'Odontologie, CHU Clermont-Ferrand, Clermont-Ferrand, F-63000, France
| | - Myriam Antri
- Neuro-Dol, Clermont Université, Université D'Auvergne, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107, Clermont-Ferrand, F-63100, France
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Czaja K, Fornaro M, Geuna S. Neurogenesis in the adult peripheral nervous system. Neural Regen Res 2015; 7:1047-54. [PMID: 25722694 PMCID: PMC4340017 DOI: 10.3969/j.issn.1673-5374.2012.14.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 02/24/2012] [Indexed: 12/21/2022] Open
Abstract
Most researchers believe that neurogenesis in mature mammals is restricted only to the subgranular zone of the dentate gyrus and the subventricular zone of the lateral ventricle in the central nervous system. In the peripheral nervous system, neurogenesis is thought to be active only during prenatal development, with the exception of the olfactory neuroepithelium. However, sensory ganglia in the adult peripheral nervous system have been reported to contain precursor cells that can proliferate in vitro and be induced to differentiate into neurons. The occurrence of insult-induced neurogenesis, which has been reported by several investigators in the brain, is limited to a few recent reports for the peripheral nervous system. These reports suggest that damage to the adult nervous system induces mechanisms similar to those that control the generation of new neurons during prenatal development. Understanding conditions under which neurogenesis can be induced in physiologically non-neurogenic regions in adults is one of the major challenges for developing therapeutic strategies to repair neurological damage. However, the induced neurogenesis in the peripheral nervous system is still largely unexplored. This review presents the history of research on adult neurogenesis in the peripheral nervous system, which dates back more than 100 years and reveals the evidence on the under estimated potential for generation of new neurons in the adult peripheral nervous system.
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Affiliation(s)
- Krzysztof Czaja
- Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology (VCAPP), College of Veterinary Medicine, Washington State University, Pullman, WA 99163-6520, USA
| | - Michele Fornaro
- Department of Anatomy, Chicago College of Osteopathic Medicine (CCOM), Midwestern University, Downers Grove, IL 60515, USA
| | - Stefano Geuna
- Neuroscience Institute of the Cavalieri Ottolenghi Foundation (NICO) & Department of Clinical and Biological Sciences, University of Turin, Orbassano 10043, Italy
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Stereological and allometric studies on neurons and axo-dendritic synapses in superior cervical ganglia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014. [PMID: 24952916 DOI: 10.1016/b978-0-12-800179-0.00002-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
The superior cervical ganglion (SCG) plays an important role in neuropathies including Horner's syndrome, stroke, and epilepsy. While mammalian SCGs seem to share certain organizational features, they display natural differences related to the animal size and side and the complexity and synaptic coverage of their dendritic arborizations. However, apart from the rat SCG, there is little information concerning the number of SCG neurons and synapses, and the nature of relationships between body weight and the numbers and sizes of neurons and synapses remain uncertain. In the recognition of this gap in the literature, in this chapter, we reviewed the current knowledge on the SCG structure and its remodeling during postnatal development across a plethora of large mammalian species, focusing on exotic rodents and domestic animals. Instrumentally, we present stereology as a state-of-the-art 3D technology to assess the SCG 3D structure unbiasedly and suggest future research directions on this topic.
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Koike T, Wakabayashi T, Mori T, Takamori Y, Hirahara Y, Yamada H. Sox2 in the adult rat sensory nervous system. Histochem Cell Biol 2013; 141:301-9. [PMID: 24170317 DOI: 10.1007/s00418-013-1158-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2013] [Indexed: 01/06/2023]
Abstract
Sex-determining region Y (SRY)-box 2 (Sox2) is a member of the Sox family transcription factors. In the central nervous system, Sox2 is expressed in neural stem cells from neurogenic regions, and regulates stem cell proliferation and differentiation. In the peripheral nervous system, Sox2 is found only in the immature and dedifferentiated Schwann cells, and is involved in myelination inhibition or N-cadherin redistribution. In the present immunohistochemical study, we found that Sox2 is also expressed in other cells of the adult rat peripheral nervous system. Nuclear Sox2 was observed in all satellite glial cells, non-myelinating Schwann cells, and the majority of terminal Schwann cells that form lamellar corpuscles and longitudinal lanceolate endings. Sox2 was not found in myelinating Schwann cells and terminal Schwann cells of subepidermal free nerve endings. Satellite glial cells exhibit strong Sox2 immunoreactivity, whereas non-myelinating Schwann cells show weak immunoreactivity. RT-PCR confirmed the presence of Sox2 mRNA, indicating that the cells are likely Sox2 expressors. Our findings suggest that the role of Sox2 in the peripheral nervous system may be cell-type-dependent.
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Ladd AABL, Ladd FVL, da Silva AAP, Oliveira MF, de Souza RR, Coppi AA. SCG postnatal remodelling--hypertrophy and neuron number stability--in Spix's yellow-toothed cavies (Galea spixii). Int J Dev Neurosci 2011; 30:129-37. [PMID: 22212604 DOI: 10.1016/j.ijdevneu.2011.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 12/04/2011] [Accepted: 12/04/2011] [Indexed: 02/05/2023] Open
Abstract
Whilst a fall in neuron numbers seems a common pattern during postnatal development, several authors have nonetheless reported an increase in neuron number, which may be associated with any one of a number of possible processes encapsulating either neurogenesis or late maturation and incomplete differentiation. Recent publications have thus added further fuel to the notion that a postnatal neurogenesis may indeed exist in sympathetic ganglia. In the light of these uncertainties surrounding the effects exerted by postnatal development on the number of superior cervical ganglion (SCG) neurons, we have used state-of-the-art design-based stereology to investigate the quantitative structure of SCG at four distinct timepoints after birth, viz., 1-3 days, 1 month, 12 months and 36 months. The main effects exerted by ageing on the SCG structure were: (i) a 77% increase in ganglion volume; (ii) stability in the total number of the whole population of SCG nerve cells (no change--either increase or decrease) during post-natal development; (iii) a higher proportion of uninucleate neurons to binucleate neurons only in newborn animals; (iv) a 130% increase in the volume of uninucleate cell bodies; and (v) the presence of BrdU positive neurons in animals at all ages. At the time of writing our results support the idea that neurogenesis takes place in the SCG of preás, albeit it warrants confirmation by further markers. We also hypothesise that a portfolio of other mechanisms: cell repair, maturation, differentiation and death may be equally intertwined and implicated in the numerical stability of SCG neurons during postnatal development.
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Affiliation(s)
- Aliny A B Lobo Ladd
- Laboratory of Stochastic Stereology and Chemical Anatomy (LSSCA)(1), Department of Surgery, College of Veterinary Medicine, University of São Paulo (USP), São Paulo, Brazil
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Dosa S, Castellanos K, Bacsa S, Gagyi E, Kovacs SK, Valyi-Nagy K, Shukla D, Dermody TS, Valyi-Nagy T. Chronic progressive deficits in neuron size, density and number in the trigeminal ganglia of mice latently infected with herpes simplex virus. Brain Pathol 2011; 21:583-93. [PMID: 21371157 DOI: 10.1111/j.1750-3639.2011.00485.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Numerous epidemiological studies have proposed a link between herpes simplex virus (HSV) infection and several common chronic neuropsychiatric and neurodegenerative diseases. Experimental HSV infection of mice can lead to chronic behavioral and neurological deficits and chronic pain. While neuron injury and loss are well-documented consequences of the acute phase of infection, the pathologic consequences of latent HSV infection are poorly understood. To determine whether latent HSV infection can cause neuronal injury in mice, trigeminal ganglia (TG) derived from adult BALB/c mice 1, 12 and 31 weeks after corneal HSV type 1 (HSV-1) inoculation were analyzed for evidence of productive or latent HSV-1 infection, inflammation and changes in neuron size, density and number. We found that latent HSV-1 infection between 12 and 31 weeks after corneal virus inoculation was associated with inflammation and progressive deficits in mean neuron diameter, neuronal nucleus diameter, neuron density and neuron number in the TG relative to mock-infected controls. The extent of neuronal injury during latent infection correlated with the extent of inflammation. These studies demonstrate that latent HSV infection is associated with progressive neuronal pathology and may lead to a better understanding of the role of HSV infections in chronic neurological diseases.
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Affiliation(s)
- Sandor Dosa
- Department of Pathology, University of Illinois at Chicago, College of Medicine, Chicago, IL 60612, USA
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Gallaher ZR, Ryu V, Larios RM, Sprunger LK, Czaja K. Neural proliferation and restoration of neurochemical phenotypes and compromised functions following capsaicin-induced neuronal damage in the nodose ganglion of the adult rat. Front Neurosci 2011; 5:12. [PMID: 21344007 PMCID: PMC3034227 DOI: 10.3389/fnins.2011.00012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 01/20/2011] [Indexed: 11/23/2022] Open
Abstract
We previously reported that neuronal numbers within adult nodose ganglia (NG) were restored to normal levels 60 days following the capsaicin-induced destruction of nearly half of the neuronal population. However, the nature of this neuronal replacement is not known. Therefore, we aimed to characterize neural proliferation, neurochemical phenotypes, and functional recovery within adult rat NG neurons following capsaicin-induced damage. Sprague-Dawley rats received intraperitoneal injections of capsaicin or vehicle solution, followed by 5-bromo-2-deoxyuridine (BrdU) injections to reveal cellular proliferation. NG were collected at multiple times post-treatment (up to 300 days) and processed for immunofluorescence, RT-PCR, and dispersed cell cultures. Capsaicin-induced cellular proliferation, indicated by BrdU/Ki-67-labeled cells, suggests that lost neurons were replaced through cell division. NG cells expressed the stem cell marker, nestin, indicating that these ganglia have the capacity to generate new neurons. BrdU-incorporation within β-III tubulin-positive neuronal profiles following capsaicin suggests that proliferating cells matured to become neurons. NG neurons displayed decreased NMDAR expression up to 180-days post-capsaicin. However, both NMDAR expression within the NG and synaptophysin expression within the central target of NG neurons, the NTS, were restored to pre-injury levels by 300 days. NG cultures from capsaicin-treated rats contained bipolar neurons, normally found only during development. To test the functional recovery of NG neurons, we injected the satiety molecule, CCK. The effect of CCK on food intake was restored by 300-days post-capsaicin. This restoration may be due to the regeneration of damaged NG neurons or generation of functional neurons that replaced lost connections.
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Affiliation(s)
- Zachary Rex Gallaher
- Programs in Neuroscience, Department of Veterinary Comparative Anatomy, Pharmacology, and Physiology, College of Veterinary Medicine, Washington State University Pullman, WA, USA
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Singh RP, Cheng YH, Nelson P, Zhou FC. Retentive multipotency of adult dorsal root ganglia stem cells. Cell Transplant 2009; 18:55-68. [PMID: 19476209 DOI: 10.3727/096368909788237177] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Preservation of neural stem cells (NSCs) in the adult peripheral nervous system (PNS) has recently been confirmed. However, it is not clear whether peripheral NSCs possess predestined, bona fide phenotypes or a response to innate developmental cues. In this study, we first demonstrated the longevity, multipotency, and high fidelity of sensory features of postmigrating adult dorsal root ganglia (aDRG) stem cells. Derived from aDRG and after 4-5 years in culture without dissociating, the aDRG NSCs were found capable of proliferation, expressing neuroepithelial, neuronal, and glial markers. Remarkably, these aDRG NSCs expressed sensory neuronal markers vesicular glutamate transporter 2 (VGluT2--glutamate terminals), transient receptor potential vanilloid 1 (TrpV1--capsaicin sensitive), phosphorylated 200 kDa neurofilaments (pNF200--capsaicin insensitive, myelinated), and the serotonin transporter (5-HTT), which normally is transiently expressed in developing DRG. Furthermore, in response to neurotrophins, the aDRG NSCs enhanced TrpV1 expression upon exposure to nerve growth factor (NGF), but not to brain-derived neurotrophic factor (BDNF). On the contrary, BDNF increased the expression of NeuN. Third, the characterization of aDRG NSCs was demonstrated by transplantation of red fluorescent-expressing aDRG NSCs into injured spinal cord. These cells expressed nestin, Hu, and beta-III-tubulin (immature neuronal markers), GFAP (astrocyte marker) as well as sensory neural marker TrpV1 (capsaicin sensitive) and pNF200 (mature, capsaicin insensitive, myelinated). Our results demonstrated that the postmigrating neural crest adult DRG stem cells not only preserved their multipotency but also were retentive in sensory potency despite the age and long-term ex vivo status.
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Affiliation(s)
- Rabindra P Singh
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Melo SR, Nyengaard JR, da Roza Oliveira F, Ladd FVL, Abrahão LMB, Machado MR, Sasahara TH, de Melo MP, Ribeiro AAC. The Developing Left Superior Cervical Ganglion of Pacas(Agouti paca). Anat Rec (Hoboken) 2009; 292:966-75. [DOI: 10.1002/ar.20918] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Vukojevic K, Skobic H, Saraga-Babic M. Proliferation and differentiation of glial and neuronal progenitors in the development of human spinal ganglia. Differentiation 2009; 78:91-8. [PMID: 19535199 DOI: 10.1016/j.diff.2009.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 03/12/2009] [Accepted: 05/20/2009] [Indexed: 11/26/2022]
Abstract
Development and differentiation of the spinal ganglia were investigated in 10 human embryos and foetuses, ranging in age between 5th and 10th developmental weeks. The aim of the study was to estimate the spatial and temporal appearance, percentage and duration of proliferation process among neural crest cells and differentiating glial cells and neurons. The process of proliferation and differentiation of cell lineages from neural crest to neurons or glial cell was analysed using immunohistochemical and immunofluorescence methods in paraffin sections. Quantification of reacting cells was performed by counting the ratio of cells stained or double-stained to specific antibodies in the number of total cell population. Data were expressed as mean+/-SD, while the difference between dorsal and ventral parts of the spinal ganglia were analysed by the Mann-Whitney test. The Ki-67 proliferation marker had the strongest expression in the 5th and 6th developmental weeks (42% of positive cells), showing also significantly higher proliferation rate in the dorsal parts of the spinal ganglia than in the ventral parts (Mann-Whitney, p=0.003). During further development, the number of proliferating cells subsequently decreased to 32% in the foetal period. A majority of the proliferating cells expressed neural crest marker nestin (71.5%) or glial cell marker S100 protein (17%). Neurons (stained with PGP9.5 marker) showed no signs of proliferation. Some cells co-expressed both neural crest cells and glial cell markers. Our results indicate the highest proliferation activity of the progenitor neural crest cells, which slightly decreased with progression of spinal ganglia differentiation. On the contrary, glial cells displayed increasing proliferation activity at later developmental stages, thus conforming significance of gliogenesis during human spinal ganglia development. Although neurogenesis was not found during the investigated period, we could not exclude the possibility of neuronal differentiation from neural crest cells, or even immature glial cells.
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Affiliation(s)
- Katarina Vukojevic
- Department of Anatomy, Histology and Embryology, School of Medicine, University of Split, Soltanska 2, 21000 Split, Croatia.
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Toscano CP, de Melo MP, Matera JM, Loesch A, Ribeiro AACM. The developing and restructuring superior cervical ganglion of guinea pigs (Cavia porcellus var. albina). Int J Dev Neurosci 2009; 27:329-36. [PMID: 19454276 DOI: 10.1016/j.ijdevneu.2009.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 02/05/2009] [Accepted: 03/15/2009] [Indexed: 11/19/2022] Open
Abstract
Post-natal development comprises both maturation (from newborn to adult) and ageing (from adult to senility) and, during this phase, several adaptive mechanisms occur in sympathetic ganglia, albeit they are not fully understood. Therefore, the present study aimed at detecting whether post-natal development would exert any effect on the size and number of a guinea pig's superior cervical ganglion (SCG) neurons. Twenty right SCGs from male subjects were used at four ages, i.e. newborn (7 days), young (30 days), adult (7 months) and old animals (50 months). Using design-based stereological methods the volume of ganglion and the total number of mononucleate and binucleate neurons were estimated. Furthermore, the mean perikaryal volume of mononucleate and binucleate neurons was estimated using the vertical nucleator. The main findings of this study were a combination of post-natal-dependent increases and decreases in some variables: (i) 27% increase in ganglion volume, (ii) 24% and 43% decreases in the total number of mono and binucleate neurons, respectively, and (iii) 27.5% and 40% decreases in the mean perikaryal volume of mono and binucleate neurons, respectively. Despite the fall in neuron numbers found here, post-natal development is not only associated with neuron loss, but also embraces other structural adaptive mechanisms, which are discussed in this paper.
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Affiliation(s)
- Cauê Pereira Toscano
- Laboratory of Stochastic Stereology and Chemical Anatomy (LSSCA), Department of Surgery, College of Veterinary Medicine, University of São Paulo (USP), São Paulo, Brazil
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Adult dorsal root ganglia sensory neurons express the early neuronal fate marker doublecortin. J Comp Neurol 2008; 511:318-28. [DOI: 10.1002/cne.21845] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Abrahão LMB, Nyengaard JR, Sasahara THDC, Gomes SP, Oliveira FDR, Ladd FVL, Ladd AABL, Melo MPD, Machado MRF, Melo SR, Ribeiro AACM. Asymmetric post-natal development of superior cervical ganglion of paca (Agouti paca). Int J Dev Neurosci 2008; 27:37-45. [PMID: 19026737 DOI: 10.1016/j.ijdevneu.2008.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 09/16/2008] [Accepted: 10/01/2008] [Indexed: 11/16/2022] Open
Abstract
Functional asymmetry has been reported in sympathetic ganglia. Although there are few studies reporting on body side-related morphoquantitative changes in sympathetic ganglion neurons, none of them have used design-based stereological methods to address this issue during post-natal development. We therefore aimed at detecting possible asymmetry-related effects on the quantitative structure of the superior cervical ganglion (SCG) from pacas during ageing, using very precise design-based stereological methods. Forty (twenty left and twenty right) SCG from twenty male pacas were studied at four different ages, i.e. newborn, young, adult and aged animals. By using design-based stereological methods the total volume of ganglion and the total number of mononucleate and binucleate neurons were estimated. Furthermore, the mean perikaryal volume of mononucleate and binucleate neurons was estimated, using the vertical nucleator. The main findings of this study were: (1) the right SCG from aged pacas has more mononucleate and binucleate neurons than the left SCG in all other combinations of body side and animal age, showing the effect of the interaction between asymmetry (right side) and animal age, and (2) right SCG neurons (mono and binucleate) are bigger than the left SCG neurons (mono and binucleate), irrespective of the animal age. This shows, therefore, the exclusive effect of asymmetry (right side). At the time of writing there is still no conclusive explanation for some SCG quantitative changes exclusively assigned to asymmetry (right side) and those assigned to the interaction between asymmetry (right side) and senescence in pacas. We therefore suggest that forthcoming studies should focus on the functional consequences of SCG structural asymmetry during post-natal development. Another interesting investigation would be to examine the interaction between ganglia and their innervation targets using anterograde and retrograde neurotracers. Would differences in the size of target organs explain ganglia structural asymmetry?
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Affiliation(s)
- Luciana Maria Bigaram Abrahão
- Laboratory of Stochastic Stereology and Chemical Anatomy (LSSCA), Department of Surgery, College of Veterinary Medicine, University of São Paulo (USP), São Paulo, Brazil
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Luzzati F, Bonfanti L, Fasolo A, Peretto P. DCX and PSA-NCAM expression identifies a population of neurons preferentially distributed in associative areas of different pallial derivatives and vertebrate species. ACTA ACUST UNITED AC 2008; 19:1028-41. [PMID: 18832334 DOI: 10.1093/cercor/bhn145] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In adult rodents, doublecortin (DCX) and polysialylated neural cell adhesion molecule (PSA-NCAM) expression is mostly restricted to newly generated neurons. These molecules have also been described in prenatally generated cells of the piriform cortex and, to a lesser extent, neocortex (NC) of the rat. In addition, PSA-NCAM+ cells have been identified in several telencephalic regions of the lizard. Here, through immunohistochemistry and 3-dimensional reconstruction, we have investigated distribution, morphology, and phenotype of DCX/PSA-NCAM-expressing cells in the pallium of different mammals and in lizard. In all species, a population of nonnewly-generated pallial DCX+/PSA-NCAM+ cells shows common morphological and phenotypic characteristics, including expression of Tbr-1, a transcription factor expressed in pallial projection neurons, and preferential distribution in associative areas. In the guinea pig and rabbit, DCX+/PSA-NCAM+ elements are also abundant in the NC, particularly in areas implicated in nonspatial learning and memory networks. In reptiles, DCX+/PSA-NCAM+ cells are located in the lateral and medial cortex and dorsal ventricular ridge but not in the dorsal cortex. These data support the fact that coexpression of DCX+/PSA-NCAM+/Tbr-1+ in the adult brain identifies evolutionary conserved cell populations shared by different pallial derivatives including the mammalian NC.
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Affiliation(s)
- Federico Luzzati
- Department of Animal and Human Biology, University of Turin, Via Accademia Albertina 13, 10153 Turin, Italy.
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Lagares A, Li HY, Zhou XF, Avendaño C. Primary sensory neuron addition in the adult rat trigeminal ganglion: evidence for neural crest glio-neuronal precursor maturation. J Neurosci 2007; 27:7939-53. [PMID: 17652585 PMCID: PMC6672737 DOI: 10.1523/jneurosci.1203-07.2007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It is debated whether primary sensory neurons of the dorsal root ganglia increase the number in adult animals and, if so, whether the increase is attributable to postnatal neurogenesis or maturation of dormant, postmitotic precursors. Similar studies are lacking in the trigeminal ganglion (TG). Here we demonstrate by stereological methods that the number of neurons in the TG of adult male rats nearly doubles between the third and eighth months of age. The increase is mainly attributable to the addition of small, B-type neurons, with a smaller contribution of large, A-neurons. We looked for possible proliferative or maturation mechanisms that could explain this dramatic postnatal expansion in neuron number, using bromodeoxyuridine (BrdU) labeling, immunocytochemistry for neural precursor cell antigens, retrograde tracing identification of peripherally projecting neurons, and in vitro isolation of precursor cells from adult TG explant cultures. Cell proliferation identified months after an extended BrdU administration was sparse and essentially corresponded to glial cells. No BrdU-labeled cell took up the peripherally injected tracer, and only a negligible number coexpressed BrdU and the pan-neuronal tracer neuron-specific enolase. In contrast, a population of cells not recognizable as mature neurons in the TG and neighboring nerve expressed neuronal precursor antigens, and neural crest glioneuronal precursor cells were successfully isolated from adult TG explants. Our data suggest that a protracted maturation process persists in the TG that can be responsible for the neuronal addition found in the adult rat.
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Affiliation(s)
- Alfonso Lagares
- Department of Anatomy, Histology, and Neuroscience, Autonoma University of Madrid, Medical School, 28029 Madrid, Spain
- Department of Neurosurgery, Hospital 12 de Octubre, 28041 Madrid, Spain, and
| | - Hong-Yun Li
- Department of Human Physiology, Centre for Neuroscience, Flinders University, Adelaide 5001, South Australia, Australia
| | - Xin-Fu Zhou
- Department of Human Physiology, Centre for Neuroscience, Flinders University, Adelaide 5001, South Australia, Australia
| | - Carlos Avendaño
- Department of Anatomy, Histology, and Neuroscience, Autonoma University of Madrid, Medical School, 28029 Madrid, Spain
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Prodanov D, Feirabend HKP. Morphometric analysis of the fiber populations of the rat sciatic nerve, its spinal roots, and its major branches. J Comp Neurol 2007; 503:85-100. [PMID: 17480027 DOI: 10.1002/cne.21375] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Correspondence between the nerve composition and the functional characteristics of its fiber populations is not always evident. To investigate such correspondence and to give a systematic picture of the morphology of the rat hind limb nerves, extensive morphometric study was performed on the sciatic nerve, its founding dorsal and ventral spinal roots, and its major branches. Nerve histology was examined in semithin sections via microscopic image analysis. Variation in the density of myelinated fibers, fiber interspace, and nerve cross-sectional area was studied in individual roots and nerves. In the dorsal roots, fiber numbers and cross-sectional areas were directly linearly proportional to the spinal root level number. Constituent fiber populations were identified using multicomponent lognormal models, and an optimal model for every nerve or root was selected by using an information theoretic approach. For the dorsal and ventral roots and the sciatic and peroneal nerves, optimal fiber population models consisted of three components, whereas, for the tibial and sural nerves, two components were optimal. Functional identities of the revealed fiber populations were established by using calculations of corresponding conduction velocities according to Arbuthnott et al. (J. Physiol. [1980] 308:125-157) and anatomical considerations. It is anticipated that morphological parameters established in this study would advance the development of neural prostheses in humans. The proximodistal correspondences among the fiber populations of different nerves were established by parametric statistical comparisons. The proposed approach provides a conceptual framework for understanding the comparative anatomy of the peripheral nerves and spinal roots and can be further applied in other species.
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Affiliation(s)
- Dimiter Prodanov
- Department of Neurosurgery, Research Laboratory, Leiden University Medical Center (LUMC), Leiden, The Netherlands
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18
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Li HY, Say EHM, Zhou XF. Isolation and Characterization of Neural Crest Progenitors from Adult Dorsal Root Ganglia. Stem Cells 2007; 25:2053-65. [PMID: 17525237 DOI: 10.1634/stemcells.2007-0080] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
After peripheral nerve injury, the number of sensory neurons in the adult dorsal root ganglia (DRG) is initially reduced but recovers to a normal level several months later. The mechanisms underlying the neuronal recovery after injury are not clear. Here, we showed that in the DRG explant culture, a subpopulation of cells that emigrated out from adult rat DRG expressed nestin and p75 neurotrophin receptor and formed clusters and spheres. They differentiated into neurons, glia, and smooth muscle cells in the presence or absence of serum and formed secondary and tertiary neurospheres in cloning assays. Molecular expression analysis demonstrated the characteristics of neural crest progenitors and their potential for neuronal differentiation by expressing a set of well-defined genes related to adult stem cells niches and neuronal fate decision. Under the influence of neurotrophic factors, some of these progenitors gave rise to neuropeptide-expressing cells and protein zero-expressing Schwann cells. In a 5-bromo-2'-deoxyuridine chasing study, we showed that these progenitors likely originate from satellite glial cells. Our study suggests that a subpopulation of glia in adult DRG is likely to be progenitors for neurons and glia and may play a role in neurogenesis after nerve injury. Disclosure of potential conflicts of interest is found at the end of this article.
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Affiliation(s)
- Hong-Yun Li
- Department of Human Physiology, Flinders University, Adelaide, SA, Australia
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19
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Arora DK, Cosgrave AS, Howard MR, Bubb V, Quinn JP, Thippeswamy T. Evidence of Postnatal Neurogenesis in Dorsal Root Ganglion: Role of Nitric Oxide and Neuronal Restrictive Silencer Transcription Factor. J Mol Neurosci 2007; 32:97-107. [PMID: 17873293 DOI: 10.1007/s12031-007-0014-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Revised: 11/30/1999] [Accepted: 02/06/2007] [Indexed: 01/18/2023]
Abstract
The various mechanisms underlying postnatal neurogenesis from discrete CNS regions have emerged recently. However, little is known about postnatal neurogenesis in dorsal root ganglion (DRG). BrdU incorporation and subsequent immunostaining for BrdU, neural stem cell marker, nestin and neuronal marker, PGP 9.5 have provided evidence for postnatal neurogenesis in DRG. We further demonstrate, in vivo and in vitro, that nitric oxide (NO) regulates neural stem cells (nestin+) proliferation and, possibly, differentiation into neurons. Surprisingly, nerve growth factor (NGF) had no effect on nestin+ cells proliferation. Axotomy or NGF-deprivation of DRG neurons-satellite glia co-culture increases NO production by neurons and treating with a NO synthase (NOS) inhibitor, N G-nitro-L-arginine methylester (L-NAME) in vitro or 7-nitroindazole (7NI) in vivo, causes a significant increase in nestin+ cell numbers. However, a soluble guanylyl cyclase (sGC) blocker, 1H-[1, 2, 4] oxadiazolo [4, 3-a] quinoxalin-1-one (ODQ) treatment of NGF-deprived DRG neurons-satellite glia co-culture had no significant effect on nestin+ cell numbers. This implies NO regulates nestin+ cell proliferation independent of cGMP. We hypothesised that the neuronal-restrictive silencer transcription factor (NRSF, also termed REST), a master regulator of neuronal genes in non-neuronal cells, may be modulated by NO in satellite glia cultures. A NO donor, dimethyl-triamino-benzidine (DETA)-NO treatment of satellite glia cell cultures results in a significant increase in the NRSF/REST mRNA expression. The majority of cultured satellite glia cells express nestin, and also show increased levels of NOS, thus L-NAME treatment of these cultures causes a dramatic reduction in NRSF/REST mRNA. Overall these results suggest that NO inhibits neurogenesis in DRG and this is correlated with modulation of NRSF, a known modulator of differentiation.
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Affiliation(s)
- Daleep K Arora
- Department of Veterinary Preclinical Sciences, University of Liverpool, Liverpool, UK
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20
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Ribeiro AACM. Size and number of binucleate and mononucleate superior cervical ganglion neurons in young capybaras. ACTA ACUST UNITED AC 2006; 211:607-17. [PMID: 17006659 DOI: 10.1007/s00429-006-0113-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2006] [Indexed: 11/27/2022]
Abstract
The total number of neurons in the superior cervical ganglion (SCG) of adult capybaras is known from a previous study, where a marked occurrence of binucleate neurons (13%) was also noted. Here, distribution, number and fate of binucleate neurons were examined in younger, developing capybaras, aged 3 months. The mean neuronal cross-sectional area was 575.2 microm2 for mononucleate neurons and 806.8 microm2 in binucleate neurons. Frequency of binucleate neurons was about 36%. The mean ganglion volume was about 190 mm3 in young capybaras and the mean neuronal density was about 9,517 neurons/mm3. The total number of neurons per ganglion was about 1.81 mill. Neuronal cell bodies constituted 22.5% of the ganglion volume and the average neuronal volume was 23,600 microm3. By comparing the present data with those previously published the conclusion is drawn that the maturation period was characterized by the following points: a 26% remarkable decrease in neuronal density which was significant (P < 0.05) and a significant 16% (P < 0.05) decrease in the total number of SCG neurons accompanied by a 23% decrease in the total number of SCG binucleate neurons.
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Guseva D, Chelyshev Y. The Plasticity of the DRG Neurons Belonging to Different Subpopulations After Dorsal Rhizotomy. Cell Mol Neurobiol 2006; 26:1225-34. [PMID: 16625433 DOI: 10.1007/s10571-006-9005-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2005] [Accepted: 01/05/2006] [Indexed: 12/19/2022]
Abstract
1. The plasticity of sensory neurons following the injury to their axons is very important for prognosis of recovery of afferent fibers with different modality. It is evident that the response of dorsal root ganglion (DRG) neurons after peripheral axotomy is different depending on the deficiency in neurotrophic factors from peripheral region. The loss of cells appears earlier and is more severe in B-cells (small, dark cells with unmyelinated axons) than in A-cells (large, light cells with myelinated axons). 2. We studied using immunohistochemical methods the response of DRG neurons to dorsal rhizotomy and combined injury of central and peripheral neuronal processes. A quantitative analysis of DRG neurons tagged by the selective markers isolectin B4 (IB4) and the heavy molecular component of the neurofilament triplet (NF200) antibody, selective for subpopulations of small and large/medium DRG neurons, respectively, was performed after dorsal rhizotomy, peripheral axotomy, and their combination. 3. The number of NF200(+)-neurons is reduced substantially after both dorsal rhizotomy and peripheral axotomy, while the decrease of IB4(+)-neurons is observed only in combined injury, i.e., dorsal rhizotomy accompanied with sciatic nerve injury. 4. Our results show that distinct subpopulations of DRG neurons respond differently to the injury of their central processes. The number of NF200(+)-neurons decreases to greater degree following dorsal rhizotomy in comparison to IB4(+)-neurons.
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Affiliation(s)
- Daria Guseva
- Histology, Cytology and Embryology Department, Kazan State Medical University (KSMU), 420012 Butlerov Street 49, Kazan, Russia.
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Malone JI, Hanna SK, Saporta S. Hyperglycemic brain injury in the rat. Brain Res 2006; 1076:9-15. [PMID: 16487498 DOI: 10.1016/j.brainres.2005.12.072] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Revised: 12/12/2005] [Accepted: 12/15/2005] [Indexed: 11/15/2022]
Abstract
Children with diabetes onset before 5 years of age have reduced neurocognitive function. This problem has been attributed to hypoglycemia, a complication of insulin therapy. The eye, kidney, and nerve complications of diabetes (hyperglycemia) have been reduced by intensified insulin therapy which is associated with a 3-fold increase in severe hypoglycemia and therefore is not recommended for children less than 13 years of age. Since hyperglycemia is much more common than intermittent hypoglycemia during early childhood diabetes, it is important to determine if hyperglycemia affects brain growth and development. Rats were exposed to 4 weeks of either continuous hyperglycemia (diabetes) or intermittent (3 h, 3 times/week) hypoglycemia from 4 to 8 weeks of age. The brains of these animals were compared to those of similarly aged normal control animals. The cell number was increased, and the cell size reduced in the cortex of diabetic animals as assessed by DNA/wet weight of brain and protein/DNA content. Reduced amounts of protein, fatty acids, and cholesterol/microgram DNA also indicate smaller cells with reduced myelin content in the cortex of the diabetic animals. Histologic evaluation of these brains confirmed the biochemical findings. These observations require further confirmation and evaluation but indicate that continuous hyperglycemia may be more damaging than intermittent hypoglycemia to the developing brain. This is an important consideration for the management of diabetes mellitus in young children.
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Affiliation(s)
- John I Malone
- Department of Pediatrics, College of Medicine, University of South Florida, Tampa, FL 33612, USA.
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Kuo LT, Simpson A, Schänzer A, Tse J, An SF, Scaravilli F, Groves MJ. Effects of systemically administered NT-3 on sensory neuron loss and nestin expression following axotomy. J Comp Neurol 2005; 482:320-32. [PMID: 15669078 DOI: 10.1002/cne.20400] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Previous work has shown that administration of the neurotrophin NT-3 intrathecally or to the proximal stump can prevent axotomy-induced sensory neuron loss and that NT-3 can stimulate sensory neuron differentiation in vitro. We have examined the effect of axotomy and systemic NT-3 administration on neuronal loss, apoptosis (defined by morphology and activated caspase-3 immunoreactivity), and nestin expression (a protein expressed by neuronal precursor cells) in dorsal root ganglia (DRG) following axotomy of the adult rat sciatic nerve. Systemic administration of 1.25 or 5 mg of NT-3 over 1 month had no effect on the incidence of apoptotic neurons but prevented the overall loss of neurons seen at 4 weeks in vehicle-treated animals. Nestin-immunoreactive neurons began to appear 2 weeks after sciatic transection in untreated animals and steadily increased in incidence over the next 6 weeks. NT-3 administration increased the number of nestin-immunoreactive neurons at 1 month by two- to threefold. Nestin-IR neurons had a mean diameter of 20.78 +/- 2.5 microm and expressed the neuronal markers neurofilament 200, betaIII-tubulin, protein gene product 9.5, growth associated protein 43, trkA, and calcitonin gene-related peptide. Our results suggest that the presence of nestin in DRG neurons after nerve injury is due to recent differentiation and that exogenous NT-3 may prevent neuron loss by stimulating this process, rather than preventing neuron death.
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Affiliation(s)
- Lu-Ting Kuo
- Department of Molecular Neuroscience, Division of Neuropathology, Institute of Neurology, London WC1N 3BG, UK
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McPhail LT, Plunet WT, Das P, Ramer MS. The astrocytic barrier to axonal regeneration at the dorsal root entry zone is induced by rhizotomy. Eur J Neurosci 2005; 21:267-70. [PMID: 15654864 DOI: 10.1111/j.1460-9568.2004.03837.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
After dorsal rhizotomy, sensory axons fail to regenerate beyond the astrocytic glia limitans at the dorsal root entry zone (DREZ) but this inhibition can be overcome with the delivery of exogenous neurotrophin-3. We investigated whether axonal inhibition at the DREZ is constitutive or induced after dorsal rhizotomy. Primary afferent neurones from enhanced green fluorescent protein-expressing mice were transplanted into adult rat dorsal root ganglia in the presence or absence of dorsal rhizotomy. In the absence of dorsal rhizotomy mouse axons freely extended into the rat central nervous system. After host dorsal rhizotomy, mouse axons were unable to cross the DREZ. However, in rats that received a dorsal rhizotomy concomitant with intrathecal neurotrophin-3, the mouse axons were able to cross the DREZ. These results indicate that, under normal circumstances, the adult DREZ is permissive to the regeneration of adult sensory axons and that it only becomes inhibitory once dorsal root axons have been injured and astrocytes at the DREZ have become reactive.
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Affiliation(s)
- Lowell T McPhail
- ICORD (International Collaboration On Repair Discoveries), The University of British Columbia, Biosciences Building, 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada
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Gagliardo KM, De Carvalho Balieiro JC, De Souza RR, Ribeiro AACM. Postnatal-related changes in the size and total number of neurons in the caudal mesenteric ganglion of dogs: Total number of neurons can be predicted from body weight and ganglion volume. ACTA ACUST UNITED AC 2005; 286:917-29. [PMID: 16142804 DOI: 10.1002/ar.a.20233] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Aging is mostly characterized by a progressive decline of neuronal function that involves both the central and the peripheral nervous system. The aging process is accompanied by changes in either the number or the size of neurons. However, these data are controversial and not very well known in the sympathetic ganglia of large mammals. Hence, the present investigation aimed to study the dog's caudal mesenteric ganglion (CMG) in three different periods of postnatal development, searching for qualitative and quantitative alterations. The CMG is responsible for the large intestine, internal anal sphincter, and partially the urogenital system innervations. Nine dead male dogs from the Veterinary Hospital of the College of Veterinary Medicine at University of São Paulo were divided into three well-defined age groups (1-2 months old, 1-2 years old, and 5-10 years old). The stereological study was pursued using the physical disector method combined to the Cavalieri principle. The postnatal development was accompanied by an increase in the nonneuronal tissue amount and in ganglion volume. Additionally, the total number of neurons also increased during aging (from 70,140 to 1,204,516), although the neuronal density showed an opposite trend (from 29,911 to 11,500 mm(-3)). Due to the interrelation between either body weight or ganglion volume and aging in the dogs investigated in this study, it was possible to predict the total number of neurons in CMG using both body weight and ganglion volume in an attempt to verify whether or not size and total number of neurons are both allometrically and aging ruled, i.e., if either the animal's body weight and ganglion volume or aging influence these parameters. The prediction of the total number of neurons was very close to the initially estimated values.
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