2D Images of Astrocytes in the Human Principal Olivary Nucleus: Monofractal Analysis of the Morphology

Introduction: Current knowledge postulated glia as active participants in various metabolic processes within nervous tissue. The most numerous glial cells were astrocytes, and qualitative analysis divided them into two types based on their anatomical locations: fibrous and protoplasmic. The main goal of this research was to examine the morphological difference between types, analyzing four features of the image. The secondary objective of this research was to explore their morphology through maturation and aging. Materials and Methods: The material originated from bilateral sections of the human principal olivary nucleus, without disorders in the central nervous system. The brains were taken from 30 human cadavers (35 - 90 years) and cut into samples corresponding to dimensions of the principal olivary nucleus. A light microscope digitized the histological preparations. The selection of 294 images was analyzed by monofractal parameters derived from the box-counting. These parameters quantified four image properties (size, shape, complexity and homogeneity) of the glial body or whole glial cell. Results: The first results showed that images of two types of astrocytes were significantly different (p < 0.05 and higher) in all properties of whole cells. The second results examined the differences between three age groups in both types of astrocytes. The differences between groups were more evident for protoplasmic than fibrous (nine vs. three parameters). Conclusions: The main limitation of this study lies in the fact that the quantification was performed only by fractal analysis techniques. Nevertheless, a detailed monofractal analysis of astrocytes was performed for the first time. Thus, although this study can be seen as an improvement of the previous qualitative results, future research will provide the complete procedure of the image analysis.