CENTRALLY
LOCATED
GRANULAR
CYTOPLASM
OF
ULTRASTRUCTURAL ANALYSIS
N. Makarova, L. Kazaryan, E. Kalinina, V. Polyakov, G. Baranova
THE
OOCYTE:
THE
Research Center for Obstetrics, Gynecology and Perinatology named after V.I. Kulakov, Russia
In this study we characterized the ultrastructure of oocytes with centrally located granular
cytoplasm.
A 36 year-old female had secondary infertility. The couple had undergone an ICSI attempt.
Controlled ovarian stimulation was started on day 2 of the cycle with HP-hMG and rFSH. 10 000
IU of human chorionic gonadotrophin was given to trigger ovulation. In total, 9 oocytes were
recovered, only four to nine oocytes were at the MII stage. There are used cultural medium
COOK. Centrally located granular cytoplasm of the oocyte was observed in all cells. Only one to
four cells was at 2PN stage. Day 2 embryo transfer was done. Pregnancy was not achieved. At
the oocyte retrieval day immature female germ cells were processed for ultrastructural analysis
by transmission electron microscopy (TEM).
A picture of uneven distribution of the main cytoplasmic organelles is observed by TEM. In the
central cytoplasmic granularity swollen granules of hypertrophic smooth endoplasmic reticulum
(SER) surrounded by mitochondria were found. However a lot of mitochondria have a vacuolated
matrix that indicates a metabolic capacity decrease. Mitochondria are often degenerated in the
complexes SER+mitochondria. These complexes are distributed unevenly and large gaps are
created between them. Segregation of cytoplasmic complexes SER+mitochondria is observed
only in the granularity.
The present study revealed destructive changes of cytoplasmic components that are
characteristic for the initial stages of apoptosis (clustering of organelles in the cell, swelling of
smooth endoplasmic reticulum cisterns, disappearance of mitochondria and vacuolization) but
this assumption is required a further experimental confirmation.