MECHANISMS OF SMOOTH ENDOPLASMIC RETICULUM AGGREGATES CREATION
IN OOCYTE`S CYTOPLASM IN IVF CYCLES AND ITS CLINICAL RELEVANCE
(LITERATURE REVIEW)
E.V. Kovalskaya,1 N.P. Makarova,1 A.G. Syrkasheva,1,* N.V. Dolgushina,1 L.F. Kurilo 2
1 Federal State Budget Institution «Research Center for Obstetrics, Gynecology and Perinatology»,
Ministry of Healthcare of the Russian Federation,
and 2 Research Center of Medical Genetics of the Russian Academy of Medical Sciences, Moscow;
* e-mail: anast.syrkasheva@gmail.com
A large proportion of human oocytes received from exogenous gonadotropin-stimulated cycles have different
morphological attributes, or dysmorphisms. The presence of dysmorphism can affect the fertilization rate,
the embryo quality and subsequently the frequency of occurrence of implantation and pregnancy. Special attention
is paid to oocytes with cytoplasmic attributes such as alteration of cytoplasmic granularity, the appearance
of vacuoles, lipofuscin bodies and visible (large) aggregates of smooth endoplasmic reticulum. Endoplasmic reticulum
(ER) is a type of the organelle forming an interconnected network of flattened, membrane-enclosed
sacs or tubes. One of the main functions of ER in the oocyte is storage and redistribution of calcium, which provides
cell activation during fertilization. Furthermore, complex of ER and mitochondria is necessary for accumulation
of energy, synthesis of lipids and triglycerides, as well as synthesis of cytosolic and nuclear membranes
during the early stages of cleavage. The appearance of anomalously large aggregates of ER in oocytes correlates
with a low fertilization rate, low embryo quality, and pregnancy rate. The aim of the manuscript is to
summarize current understanding of the mechanism of formation of such pathology of oocytes, together with
special aspects of their fertilization and embryo quality.
Key words:
oocyte, in vitro fertilization, endoplasmic reticulum, oocyte pathology
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