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Histomorphometry in Peripheral Nerve Regeneration: Comparison of Different Axon Counting Methods. J Surg Res 2021; 268:354-362. [PMID: 34403855 DOI: 10.1016/j.jss.2021.06.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 04/16/2021] [Accepted: 06/08/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND Histomorphometry quantitatively evaluates nerve regeneration. Total myelinated fiber count (TMFC) is most accurately obtained manually across full nerve cross-sections, but most researchers opt for automated, sampled analysis. Few of the numerous techniques available have been validated. The goal of this study was to compare common histomorphometric methods (full manual [FM], sampled manual [SM], and sampled automatic [SA]) to determine their reliability and consistency. MATERIAL AND METHODS Twenty-four rats underwent sciatic nerve (SN) repair with 20mm isografts; SNs distal to the graft were analyzed. TMFC was manually determined in each full cross-section. Counts were also extrapolated from sampled fields, both manually and automatically with ImageJ software. Myelinated fiber diameter, axon diameter, and myelin sheath thickness were measured manually in full and sampled fields; G-ratio was calculated. Repeated-measures MANOVA, Spearman correlation, and Wilcoxon signed-rank tests were performed. A systematic review of histomorphometry in rat SN repair was performed to analyze the variability of techniques in the literature. RESULTS FM TMFC was 13,506 ± 4,217. Both sampled methods yielded significantly different TMFCs (SM:14.4 ± 13.4%, P< 0.001; SA:21.8 ± 44.7%, P = 0.037). All three methods strongly correlated with each other, especially FM and SM (rs = 0.912, P< 0.001). FM fiber diameter, axon diameter, and myelin sheath thickness did not differ from SM (P = 0.493, 0.209, and 0.331, respectively). 65% of papers used sampling; 78% utilized automated or semi-automated analysis. Software, sampling, and histomorphometric parameters varied widely. CONCLUSION SM and SA analysis are reliable with standardized, systematic sampling. Transparency is essential to allow comparison of data; meanwhile, researchers must be cognizant of the wide variety of methodologies in the literature.
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Wang XS, Chen X, Gu TW, Wang YX, Mi DG, Hu W. Axonotmesis-evoked plantar vasodilatation as a novel assessment of C-fiber afferent function after sciatic nerve injury in rats. Neural Regen Res 2019; 14:2164-2172. [PMID: 31397356 PMCID: PMC6788242 DOI: 10.4103/1673-5374.262595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Quantitative assessment of the recovery of nerve function, especially sensory and autonomic nerve function, remains a challenge in the field of nerve regeneration research. We previously found that neural control of vasomotor activity could be potentially harnessed to evaluate nerve function. In the present study, five different models of left sciatic nerve injury in rats were established: nerve crush injury, nerve transection/suturing, nerve defect/autografting, nerve defect/conduit repair, and nerve defect/non-regeneration. Laser Doppler perfusion imaging was used to analyze blood perfusion of the hind feet. The toe pinch test and walking track analysis were used to assess sensory and motor functions of the rat hind limb, respectively. Transmission electron microscopy was used to observe the density of unmyelinated axons in the injured sciatic nerve. Our results showed that axonotmesis-evoked vasodilatation in the foot 6 months after nerve injury/repair recovered to normal levels in the nerve crush injury group and partially in the other three repair groups; whereas the nerve defect/non-regeneration group exhibited no recovery in vasodilatation. Furthermore, the recovery index of axonotmesis-evoked vasodilatation was positively correlated with toe pinch reflex scores and the density of unmyelinated nerve fibers in the regenerated nerve. As C-fiber afferents are predominantly responsible for dilatation of the superficial vasculature in the glabrous skin in rats, the present findings indicate that axonotmesis-evoked vasodilatation can be used as a novel way to assess C-afferent function recovery after peripheral nerve injury. This study was approved by the Ethics Committee for Laboratory Animals of Nantong University of China (approval No. 20130410-006) on April 10, 2013.
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Affiliation(s)
- Xue-Song Wang
- Department of Orthopedics, The Affiliated Hospital of Jiangnan University (The Third People's Hospital of Wuxi City), Wuxi, Jiangsu Province, China
| | - Xue Chen
- Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu Province, China
| | - Tian-Wen Gu
- Key Laboratory for Neuroregeneration of Ministry of Education and Co-innovation Center for Neuroregeneration of Jiangsu Province, Nantong University, Nantong, Jiangsu Province, China
| | - Ya-Xian Wang
- Key Laboratory for Neuroregeneration of Ministry of Education and Co-innovation Center for Neuroregeneration of Jiangsu Province, Nantong University, Nantong, Jiangsu Province, China
| | - Da-Guo Mi
- Department of Orthopedics, Nantong Hospital of Traditional Chinese Medicine, Nantong, Jiangsu Province, China
| | - Wen Hu
- Key Laboratory for Neuroregeneration of Ministry of Education and Co-innovation Center for Neuroregeneration of Jiangsu Province, Nantong University, Nantong, Jiangsu Province, China
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Casal D, Mota-Silva E, Iria I, Alves S, Farinho A, Pen C, Lourenço-Silva N, Mascarenhas-Lemos L, Silva-Ferreira J, Ferraz-Oliveira M, Vassilenko V, Videira PA, Goyri-O’Neill J, Pais D. Reconstruction of a 10-mm-long median nerve gap in an ischemic environment using autologous conduits with different patterns of blood supply: A comparative study in the rat. PLoS One 2018; 13:e0195692. [PMID: 29659600 PMCID: PMC5902043 DOI: 10.1371/journal.pone.0195692] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Accepted: 03/27/2018] [Indexed: 12/19/2022] Open
Abstract
The aim of this study was to evaluate in the Wistar rat the efficacy of various autologous nerve conduits with various forms of blood supply in reconstructing a 10-mm-long gap in the median nerve (MN) under conditions of local ischemia. A 10-mm-long median nerve defect was created in the right arm. A loose silicone tube was placed around the nerve gap zone, in order to simulate a local ischemic environment. Rats were divided in the following experimental groups (each with 20 rats): the nerve Graft (NG) group, in which the excised MN segment was reattached; the conventional nerve flap (CNF) and the arterialized neurovenous flap (ANVF) groups in which the gap was bridged with homonymous median nerve flaps; the prefabricated nerve flap (PNF) group in which the gap was reconstructed with a fabricated flap created by leaving an arteriovenous fistula in contact with the sciatic nerve for 5 weeks; and the two control groups, Sham and Excision groups. In the latter group, the proximal stump of the MN nerve was ligated and no repair was performed. The rats were followed for 100 days. During this time, they did physiotherapy. Functional, electroneuromyographic and histological studies were performed. The CNF and ANVF groups presented better results than the NG group in the following assessments: grasping test, nociception, motor stimulation threshold, muscle weight, and histomorphometric evaluation. Radial deviation of the operated forepaw was more common in rats that presented worse results in the other outcome variables. Overall, CNFs and ANVFs produced a faster and more complete recovery than NGs in the reconstruction of a 10-mm-long median nerve gap in an ischemic environment in the Wistar rat. Although, results obtained with CNFs were in most cases were better than ANVFs, these differences were not statistically significant for most of the outcome variables.
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Affiliation(s)
- Diogo Casal
- Anatomy Department, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
- Plastic and Reconstructive Surgery Department and Burn Unit, Centro Hospitalar de Lisboa Central–Hospital de São José, Lisbon, Portugal
- UCIBIO, Life Sciences Department, Faculty of Sciences and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- CEDOC, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Eduarda Mota-Silva
- LIBPhys, Physics Department, Faculdade de Ciências e Tecnologias, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Inês Iria
- CEDOC, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Sara Alves
- Pathology Department, Centro Hospitalar de Lisboa Central–Hospital de São José, Lisbon, Portugal
| | - Ana Farinho
- CEDOC, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Cláudia Pen
- Pathology Department, Centro Hospitalar de Lisboa Central–Hospital de São José, Lisbon, Portugal
| | | | - Luís Mascarenhas-Lemos
- Anatomy Department, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
- Pathology Department, Centro Hospitalar de Lisboa Central–Hospital de São José, Lisbon, Portugal
| | - José Silva-Ferreira
- Pathology Department, Centro Hospitalar de Lisboa Central–Hospital de São José, Lisbon, Portugal
| | - Mário Ferraz-Oliveira
- Pathology Department, Centro Hospitalar de Lisboa Central–Hospital de São José, Lisbon, Portugal
| | - Valentina Vassilenko
- LIBPhys, Physics Department, Faculdade de Ciências e Tecnologias, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Paula Alexandra Videira
- UCIBIO, Life Sciences Department, Faculty of Sciences and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- CEDOC, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - João Goyri-O’Neill
- Anatomy Department, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Diogo Pais
- Anatomy Department, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
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Bobinski F, Martins D, Bratti T, Mazzardo-Martins L, Winkelmann-Duarte E, Guglielmo L, Santos A. Neuroprotective and neuroregenerative effects of low-intensity aerobic exercise on sciatic nerve crush injury in mice. Neuroscience 2011; 194:337-48. [DOI: 10.1016/j.neuroscience.2011.07.075] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 07/28/2011] [Accepted: 07/30/2011] [Indexed: 11/17/2022]
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Korte N, Schenk HC, Grothe C, Tipold A, Haastert-Talini K. Evaluation of periodic electrodiagnostic measurements to monitor motor recovery after different peripheral nerve lesions in the rat. Muscle Nerve 2011; 44:63-73. [DOI: 10.1002/mus.22023] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kaplan S, Geuna S, Ronchi G, Ulkay MB, von Bartheld CS. Calibration of the stereological estimation of the number of myelinated axons in the rat sciatic nerve: a multicenter study. J Neurosci Methods 2010; 187:90-9. [PMID: 20064555 DOI: 10.1016/j.jneumeth.2010.01.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 12/31/2009] [Accepted: 01/03/2010] [Indexed: 12/13/2022]
Abstract
Several sources of variability can affect stereological estimates. Here we measured the impact of potential sources of variability on numerical stereological estimates of myelinated axons in the adult rat sciatic nerve. Besides biological variation, parameters tested included two variations of stereological methods (unbiased counting frame versus 2D-disector), two sampling schemes (few large versus frequent small sampling boxes), and workstations with varying degrees of sophistication. All estimates were validated against exhaustive counts of the same nerve cross sections to obtain calibrated true numbers of myelinated axons (gold standard). In addition, we quantified errors in particle identification by comparing light microscopic and electron microscopic images of selected consecutive sections. Biological variation was 15.6%. There was no significant difference between the two stereological approaches or workstations used, but sampling schemes with few large samples yielded larger differences (20.7+/-3.7% SEM) of estimates from true values, while frequent small samples showed significantly smaller differences (12.7+/-1.9% SEM). Particle identification was accurate in 94% of cases (range: 89-98%). The most common identification error was due to profiles of Schwann cell nuclei mimicking profiles of small myelinated nerve fibers. We recommend sampling frequent small rather than few large areas, and conclude that workstations with basic stereological equipment are sufficient to obtain accurate estimates. Electron microscopic verification showed that particle misidentification had a surprisingly variable and large impact of up to 11%, corresponding to 2/3 of the biological variation (15.6%). Thus, errors in particle identification require further attention, and we provide a simple nerve fiber recognition test to assist investigators with self-testing and training.
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Affiliation(s)
- S Kaplan
- Department of Histology and Embryology, Ondokuz Mayis University School of Medicine, Samsun, Turkey
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Methylprednisolone fails to improve functional and histological outcome following spinal cord injury in rats. Exp Neurol 2009; 220:71-81. [DOI: 10.1016/j.expneurol.2009.07.030] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 07/27/2009] [Accepted: 07/28/2009] [Indexed: 11/22/2022]
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Sinis N, Kraus A, Tselis N, Haerle M, Werdin F, Schaller HE. Functional recovery after implantation of artificial nerve grafts in the rat- a systematic review. J Brachial Plex Peripher Nerve Inj 2009; 4:19. [PMID: 19852862 PMCID: PMC2770034 DOI: 10.1186/1749-7221-4-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2009] [Accepted: 10/25/2009] [Indexed: 01/26/2023] Open
Abstract
Purpose The aim of this study was to compare functional data of different nerve-gap bridging materials evaluated in rat experiments by means of a systematic review. Materials and methods A systematic review was conducted, searching MEDLINE, HTS and CENTRAL to identify all trials evaluating functional recovery of artificial nerve conduits in the rat model. Results There was a trend towards a favourable outcome of conduits coated with Schwann-cells compared to the plain synthetics. Histomorphometry, electrophysiology and muscle-weight correlated poorly with functional outcome. Conclusion Schwann-cell coated conduits showed promising results concerning functional recovery. Further standardization in outcome reporting is encouraged.
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Affiliation(s)
- Nektarios Sinis
- Clinic for Hand, Plastic, Reconstructive and Burn Surgery, BG Trauma Center, Eberhard-Karls University, Schnarrenbergstrasse 95, D-72076 Tuebingen, Germany
| | - Armin Kraus
- Clinic for Hand, Plastic, Reconstructive and Burn Surgery, BG Trauma Center, Eberhard-Karls University, Schnarrenbergstrasse 95, D-72076 Tuebingen, Germany
| | - Nikolaos Tselis
- Dept of Radiotherapy, Hospital of Offenbach, Starkenburgring 66, D-63069 Offenbach, Germany
| | - Max Haerle
- Dept of Hand and Plastic Surgery, Orthopaedic Hospital Markgroeningen, Kurt-Lindemann-Weg 10 D-71706 Markgroeningen, Germany
| | - Frank Werdin
- Clinic for Hand, Plastic, Reconstructive and Burn Surgery, BG Trauma Center, Eberhard-Karls University, Schnarrenbergstrasse 95, D-72076 Tuebingen, Germany
| | - Hans-Eberhard Schaller
- Clinic for Hand, Plastic, Reconstructive and Burn Surgery, BG Trauma Center, Eberhard-Karls University, Schnarrenbergstrasse 95, D-72076 Tuebingen, Germany
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Tos P, Ronchi G, Papalia I, Sallen V, Legagneux J, Geuna S, Giacobini‐Robecchi M. Chapter 4 Methods and Protocols in Peripheral Nerve Regeneration Experimental Research: Part I—Experimental Models. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 87:47-79. [DOI: 10.1016/s0074-7742(09)87004-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Raimondo S, Fornaro M, Di Scipio F, Ronchi G, Giacobini-Robecchi MG, Geuna S. Chapter 5: Methods and protocols in peripheral nerve regeneration experimental research: part II-morphological techniques. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 87:81-103. [PMID: 19682634 DOI: 10.1016/s0074-7742(09)87005-0] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This paper critically overviews the main procedures used for carrying out morphological analysis of peripheral nerve fibers in light, confocal, and electron microscopy. In particular, this paper emphasizes the importance of osmium tetroxide post-fixation as a useful procedure to be adopted independently from the embedding medium. In order to facilitate the use of any described techniques, all protocols are presented in full details. The pros and cons for each method are critically addressed and practical indications on the different imaging approaches are reported. Moreover, the basic rules of morpho-quantitative stereological analysis of nerve fibers are described addressing the important concepts of design-based sampling and the disector. Finally, a comparison of stereological analysis on myelinated nerve fibers between paraffin- and resin-embedded rat radial nerves is reported showing that different embedding procedures might influence the distribution of size parameters.
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Affiliation(s)
- Stefania Raimondo
- Department of Clinical and Biological Sciences, San Luigi Gonzaga School of Medicine, University of Turin, Turin 10043, Italy
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