Peripheral nerve morphometry: Comparison between manual and semi-automated methods in the analysis of a small nerve.
Manual nerve morphometry has been usually described as tedious, time consuming, difficult to perform correctly and subject to many sources of errors. The above considerations might suggest that fully automated image analysis systems could be ideally programmed to analyze myelinated fibers. However, operator intervention is necessary to manually eliminate dark tissue elements such as pericytes and Schwann cell nuclei. The aims of the present study were to compare the manual and semi-automated techniques in the evaluation of a small nerve, comparing the most commonly used morphometric parameters for nerve descriptions. The aortic depressor nerves (ADN) of male Wistar rats (N = 12) were prepared with conventional techniques for epoxy resin embedding. Manual morphometry was performed on photomicrographs using a digitizing tablet. Semi-automated morphometry was performed with the aid of computer software, on the same negative images used on the photographic procedure, which were scanned and digitized to a microcomputer. Our results show no differences between data obtained with both methods, for any of the evaluated parameters (area, perimeter, diameters, myelin sheath thickness, g ratio, distribution histograms). In conclusion, manual morphometry reproduced data obtained with semi-automated technique in a small nerve, with the advantages of being less-expensive and an affordable method.
da Silva
André Pelegrino Demétrio
AP
Department of Neurology, School of Medicine of Ribeirão Preto, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto 14049-900, SP, Brazil.
Jordão
Caroline Echavarria Rodrigues
CE
Fazan
Valéria Paula Sassoli
VP
D000715:Anatomy / Q000295:instrumentation*; D000818:Animals; D001331:Automation; D001369:Axons / Q000648:ultrastructure; D003627:Data Interpretation, Statistical; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure; D015588:Observer Variation; D010525:Peripheral Nerves / Q000033:anatomy & histology* / Q000648:ultrastructure; D010784:Photomicrography; D051381:Rats; D017208:Rats, Wistar; D012984:Software; D014584:User-Computer Interface