Med. Weter. 71 (5), 292-297, 2015

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Wawrzyniak A., Jaworska-Adamu J., Łuszczewska-Sierakowska I., Guz T.
Evaluation of morphometric parameters of three types of oligodendrocytes in the periaqueductal gray matter of rats in different age groups
The aim of the study was to evaluate selected morphometric parameters of three types of oligodendrocytes on the basis of their morphology. A total of ten male Wistar rats in two age groups, 25 weeks and 140 weeks, were used for the experiments. After the rats were sacrificed by perfusion-fixation, the midbrains with the periaqueductal grey matter were collected and embedded in celloidin. Semi-thin sections were stained with methylene blue, analysed and photographed under a light microscope. The morphometric parameters taken into account were mean cell size, mean perimeter of soma in µm and mean area of soma in µm2. In addition, the percentages of different types of oligodendrocytes in the measurement area were determined. The results obtained were analysed statistically. In the PAG of the 25-week-old rats oligodendrocytes with light cytoplasm predominated. Their average size was about 7 µm. In the 140-week-old individuals an increase was observed in the number of oligodendrocytes with medium and dark cytoplasm, and their average size was about 6.79 µm. The perimeters of the three types of oligodendrocytes were similar in the two age groups – about 20 µm. There were also no statistically significant differences in the surface area of the three types of oligodendrocytes in the 25- and 140-week-old rats. The average surface area of these cells was about 40 µm2. Oligodendrocytes have been neglected in research on older individuals and should therefore be analysed in this regard.
Key words: oligodendrocytes, morphometric parameters, periaqueductal grey matter, older rats