ULTRASTRUCTURAL AND X-RAY SPECTRAL ANALYSIS OF CELLS U-937
DURING APOPTOSIS PROCESS INDUCED BY HYPERTONY
E.S. Snigirevskaya,1 A.V. Moshkov,1 V.E. Yurinskaya,1 A.A. Vereninov,1
Ya.Yu. Komissarchik 1,2,*
1 Institute of Cytology RAS, St. Petersburg;
* e-mail: relapse@yandex.ru
The results of this work concerning ultrastructural changes of U-937 cells in a state of apoptosis are largely
in consistent with the same information available in the literature. However, we have got the original data on
the ultrastructural changes of cell organelles and immune localization and distribution of proteasomes. It has
been demonstrated that Golgi apparatus is located close to the plasma membrane in the case of apoptosis induced
by incubating the cells in a hypertonic suchrose solution (200—400 mM). The fact can be considered as an
indirect indication of depolymerization of cytoskeletal elements, in particular, MTs maintaining Golgi apparatus
in a cell centre. In the later stages of apoptosis, the distances between Golgi cisterna are significantly increased.
It can be explained by hydrolysis of golgins binding cisterna between each other. Mitochondria are not significantly
changed in these cells. They have regularly disposed crista and sufficiently dense matrix with a few
vacuoles. Proteasomes as rod-shaped osmiophilic particles (12 × 30 nm) have been revealed during each apoptosis
stage both in nuclei and cytopl;asm of cells studied. The particles form aggregates of different densitities
and sizes unlimited by membrane. It has been proposed that the particle aggregates revealed in the work are
analogous to «processing bodies» or aggresomes described in the literature. They can be detected in cells under
conditions of suppressed nucleus transcriptional processes in the nucleus and participate in storing and degradation
of various mRNAs, RNP and proteins. The changes of intracellular contents of Na and K in a single cell
during apoptosis induced by osmotic shock have been revealed using method of X-ray microanalysis. It has been
demonstrated the increase in the ratio of intracellular contents Na+/K+ in the most of apoptotic cells in comparing
with control cells.
Key words: U-937 cells, apoptotic bodies, chromatin condensation, proteasomes, microtubules,
Golgi apparatus, X-ray microanalysis, immunocytochemistry
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