Objective: As it is well known, the first stage of microscopic processes is fixation. Formaldehyde and pair of gluteraldehyde-osmium tetraoxide are commonly used in light and electron microscopical process respectively. Aim of this study was to evaluate effects of both fixatives on liver size by Cavalieri principle, a stereological technique.
Material and Methods: In the present study, 5 adult, female Sprague Dawley rats were utilized. After volumes of removed livers were determined by water immersion method, handled liver samples were fixed in 10% formaldehyde solution for light microscopical examination (group 1; n= 10 liver pieces). In electron microscopical process, it was carried out post-fixation by 1% osmium tetraoxide buffered 0.2 M phosphate after pre-fixation, made by 3% gluteraldehyde buffered with 0.2 M phosphate (group 2; n= 10 liver pieces). Then thick (5 µm), semi-thin (1 µm) sections handled from all blocks were photographed via light microscope with camera attachment and liver volumes were measured with Cavalieri principle on this images. Consequently the results of two groups were compared with each other and it was evaluated statistically.
Results: According to our results, mean liver volumes via water immersion method and liver volumes of two groups were estimated as 9.178, 9.104-8.522 mm3 respectively. Difference between both mean volume values of two groups and between volumetric values by water immersion method and the second group was significant, statistically (p< 0, 05; Independent Samples T Test).
Conclusions: In the literature, some studies are available about comparison of fixation effectiveness between formaldehyde and glutaraldehyde-osmium tetraoxide in specially immunohistochemical studies. But there is not any study concerning effects of these fixatives on liver size till now.
Finally, in this study, different effects of formaldehyde and combination of glutaraldehyde-osmium tetraoxide on liver volume were indicated with stereological approachment, an unbiased method.
Key Words: Fixation, Microscopy, Stereology, Cavalieri Principle.
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