Two nerve morphometry methods performed through the same computer program: are they comparable?

Abstract

Morphometry has been widely used in studies designed to establish normal patterns of biological structures or to compare changes resulting from pathological processes. It can be performed manually or through semi‐automatic or automatic methods. However, it is difficult to compare results between studies that used different methods. We aimed to compare the results of two different methods of nerve morphometry, automatic and semi‐automatic, using the same computer software. Female Wistar rats (n = 5) with 90 days of age had their right and left sural nerves prepared for light microscopy. Automatic and semi‐automatic morphometry was performed using the program KS‐400 and took into consideration: area and lesser diameter of myelinated fibers and their axons, the myelin sheath area and the ratio between the lesser diameter of the axon and its respective myelinated fiber (G‐ratio). The nerves are longitudinally and laterally symmetric with both morphometric methods. A significant overestimation of the myelinated fibers size and a significant underestimation of the myelinated axons size were observed with the automatic method. Our results indicate an important differences in the values of the myelinated fibers morphometry of one nerve, obtained with two different methodologies. Thus, the same methodology must be standardized and used throughout a single experiment.Grant Funding Source : FAPESP, CNPq and FAEPA