Stereological investigation of medulla oblongata volume in Norduz sheep

Authors: OZAN ERTAŞ, GAMZE ÇAKMAK

Abstract: In this study, it was aimed to stereologically examine the medulla oblongata volume of Norduz sheep in the Gürpınar District of Van Province. Upon receiving news from the sections in the Gürpınar region, we went to the region. A total of 12 Norduz sheep skulls, 6 females and 6 males, were received from the Norduz sheep slaughter in the region. After the brains of Norduz sheep were dissected, they were fixed as a whole in formaldehyde for 1 week. Medulla oblongatas were separated from the brain and kept in formaldehyde for 1 week. Tissues obtained by sequential random sampling from the medulla oblongata were used for texture tracking. After texture tracking, 10-12 sections of 5 μm thickness were taken by sequential random sampling method using a rotary microtome (Leica RM, 2135, Leica Instruments, Nussloch, Germany) using steel disposable microtome blades. These obtained sections were stained with the hematoxylin-eosin staining method and viewed under an Olympus CX31 microscope with Olympus U - TV0, 5XC - 3 Tokyo Japan. Photos taken with a 4× objective were used for volume calculations. Total medulla oblongata volume, medulla volume, and cortex volume values were calculated separately from the obtained images using the Shtereom I program. The Cavalieri's principle was used when applying stereological methods for volume calculations. In the statistical evaluation between the sexes, no difference was found in the values obtained in the comparison between the total volume values, medulla volume values, and cortex volume values between both sexes. In addition, there was no difference between the sexes in terms of medulla/total volume ratio values. However, a value of 0.004 was obtained in terms of cortex/total volume ratio values. In this case, since p < 0.005, it is possible to talk about a statistically significant difference in male and female sheep in terms of this ratio value. Again, the medulla/cortex volume ratio value was calculated to be 0.041, and a significant difference was observed in terms of this value in the evaluation between sexes. The volume calculations obtained by stereological methods were evaluated with statistical programs and all the results were presented to the literature.

Keywords: Cavalieri's principle, medulla oblongata, Norduz sheep, stereology, volume

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