58
NUCLEOLAR MIGRATION IN HEPATOCYTES OF ELDERLY INDIVIDUALS: A
MORPHOLOGICAL STUDY
Isayeva Nilufar Zubidullayevna
Phd, Senior Lecturer, Alfraganus University
Department of Medicine
https://doi.org/10.5281/zenodo.14898125
Abstract.
This study presents the results of a morphological examination of the liver in
healthy elderly individuals to investigate the process of nucleolar granular component
migration from the nucleus to the cytoplasm of hepatocytes. It was established that this process
is analogous to that observed in animals, with no fundamental differences between species. The
analysis revealed age-related morphological changes, such as lipofuscin accumulation,
dystrophic processes, and nuclear polymorphism. Special attention was given to the
characteristics of migrating nucleoli, including their shape, size, and potential mechanisms of
exit from the nucleus into the cytoplasm. The obtained data confirm the possibility of nucleolar
migration in humans and its potential role in cellular processes.
Keywords:
hepatocytes, nucleolus, migration, morphology, age-related changes,
lipofuscin, dystrophy, human liver, cellular processes, nuclear polymorphism.
Introduction.
The liver is one of the key organs of the human div, performing numerous
vital functions, including detoxification, metabolism, protein synthesis, and energy regulation.
Hepatocytes, which constitute the primary parenchymal cells of the liver, exhibit high
functional activity and morphological plasticity. One of the less studied processes occurring in
hepatocyte nuclei is the migration of the nucleolar granular component from the nucleus to the
cytoplasm.
Previously, nucleoli were considered exclusively intracellular structures involved in
ribosome biogenesis and transcription regulation. However, studies conducted on animal
models (rabbits and white rats) have demonstrated that nucleoli can exit the nucleus into the
cytoplasm, raising the question of whether a similar mechanism exists in humans [Yermolaev,
2004].
Age-related liver changes include lipofuscin accumulation, dystrophic processes, and
structural reorganization of hepatic plates, which may influence intracellular transport
mechanisms. This study examines the possibility of nucleolar migration in healthy elderly
individuals, identifies the morphological features of this process, and compares it with similar
phenomena observed in animals. The conducted research aims to provide a deeper
understanding of the mechanisms of intracellular nucleolar transport and its potential role in
human cell physiology.
Objective and Methods.
The objective of this study is to investigate the morphological
aspects of nucleolar granular component migration from the nucleus to the cytoplasm in human
hepatocytes and to determine the features of this process in healthy elderly individuals. Special
attention was given to age-related structural changes in the liver and possible mechanisms of
nucleolar exit from the nucleus.
To achieve this objective, the following research methods were employed: General
morphological analysis of liver structures using standard histological staining techniques
(hematoxylin-eosin). Light microscopy to examine the ultrastructural changes in hepatocytes
and identify morphological signs of nucleolar migration. The study was conducted using a DN-
59
300 M light microscope with a digital photo attachment at ×40 and ×100 magnification.
Histological analysis of autopsy liver samples from 22 patients (12 males and 10 females) aged
60 to 83 years, who had died from causes unrelated to liver pathology. Comparative analysis to
correlate the obtained data with findings from studies on animal models (rabbits, white rats)
to identify possible similarities and differences in the mechanism of nucleolar migration.
These methods enabled a detailed analysis of morphological changes in hepatocytes and
confirmed the possibility of nucleolar migration in humans.
Results.
The morphological study of the liver in healthy elderly individuals revealed the
migration of nucleoli from the nucleus to the cytoplasm of hepatocytes. This process was found
to be analogous to that observed in animals, without fundamental species differences.
Microscopic examination of liver structure demonstrated pronounced nuclear
polymorphism in hepatocytes. Most cells contained small to medium-sized nuclei, but
occasional large and giant nuclei were observed. Migration of nucleoli was most frequently
observed in large nuclei, where nucleoli moved from the nuclear center toward the periphery,
protruded through the nuclear envelope, and exited into the cytoplasm.
Age-related liver changes included lipofuscin accumulation in hepatocyte cytoplasm,
particularly around central veins, as well as various degrees of dystrophic processes. In most
cases, fatty, granular, and vacuolar dystrophy were observed, either in focal or diffuse forms.
A special focus was placed on structural changes in nucleoli. The study found that
primarily large nucleoli underwent migration, maintaining their integrity after exiting into the
cytoplasm. Unlike in animals, in humans, migrated nucleoli retained their volume and density.
In some cases, a high-energy ejection of nucleoli was observed, forming a characteristic "flight
to the stars" pattern.
Hepatic plates in most examined patients exhibited a disorganized structure, with
sinusoidal capillaries appearing narrowed or collapsed. In some cases, pathological changes
were observed, including nuclear membrane protrusions, nuclear matrix clearing, and the
presence of empty nuclei.
A detailed analysis confirmed that nucleolar migration predominantly occurred in
hepatocytes with multiple nucleoli (at least two), where one of the nucleoli could detach and
move into the cytoplasm. After exiting, the nucleolus remained intact for a certain period,
acquiring a rounded shape and possibly participating in cellular processes.
Thus, the study results confirmed the existence of a nucleolar migration mechanism in
humans, similar to that observed in animals.
References:
1.
Sadriddinov A. F., Isaeva N. Z. Stages Of Migration Of Nucleolus Of Hepatocytes In Some
Mammalian Species //Solid State Technology. – 2020. – Т. 63. – №. 6. – С. 15275-15283..
2.
Sadriddinov, Asomidin, et al. "The Wonderful Multifunctional Nucleolus of Hepatic
Cell."
Journal of Pharmacy and Pharmacology
3 (2015): 268-277.
3.
Fayazovich S. A. et al. Morphological aspects of natural death for hepatic cells //European
journal of biomedical and life sciences. – 2015. – №. 2. – С. 69-75.
4.
Исаева Н. З., Мухамеджанов А. Х. Сравнительный анализ ядерного аппарата
гепатоцитов млекопитающих при различных видах репаративной рSadriddinov A. et al.
60
The Wonderful Multifunctional Nucleolus of Hepatic Cell //Journal of Pharmacy and
Pharmacology. – 2015. – Т. 3. – С. 268-277.
5.
Sadriddinov A.F., Cheraliev K.S., Isaeva N.Z, Murotov O.U.The Wonderful Multifunctional
Nucleolus of Hepatic Cell. //Journal of Pharmacy and Pharmacology -2015; 268-277 (in
American)
6.
Студитский А. П. Природа и происхождение ядрышка. //Успехи современной
биологии. —1973, т. 76, с. 199—221, Россия
7.
Mikhailovskaya É.V. Migration of nucleoli and karyoplasm into the cytoplasm of reticular
cells in lymph node cultures. //
Bull Exp Biol Med-1978, №
85 p. 641–645 Ukraine
8.
Райкова Е. В. Морфология ядрышек в период роста ооцитов осетровых рыб.
//Журнал общей биологии.— 1968, т. 29, с. 316—333.
9.
Kishi K. Fine structural and cytochemical observations on cytoplasmic nucleoluslike
bodies of rat medulla oblongata. Z. Zellforsch, 1972, Bd. 132, S. 523-532.
10.
Манских В. Н., К вопросу о механизмах образования микроядер в соматических
клетках бесхвостых амфибий в норме и при действии N-нитрозо-N-метилкарбамида;
Бюллетень экспериментальной биологии и медицины, изд. Рос. акад. мед. наук (М.),
2006—том 141, №2, с. 217-220.
11.
Зацепина О.В. локализация ДНК в ядрышках клеток млекопитающих. «Цитология».
1992. т. 34.№ 5. С.34-39.
