It happens that multiple repeated IVF protocols fail. At the same time, the quality of oocytes at first glance does not cause serious doubts among embryologists.
Why might this happen?
In Vitro Fertilization depends on many factors, including the location and morphology of the spindle cell division. It is one of the most important elements of the oocyte, which regulates the distribution of genetic material.
How is the spindle apparatus formed?
Dynamic structure appears in the process of mitosis as a result of the interaction of protein molecules and nucleotides. Microtubules join at the equator of the cell to form a spindle-shaped structure.
What is a spindle apparatus?
The process of embryo development is determined by the quality of the oocyte and all its structures. What is an oocyte? This is an immature egg. The spindle apparatus contained in it determines the accuracy of the distribution of chromosomes during the cleavage process. When dividing, the genetic material must be divided strictly equally so that the development of the fetus occurs without pathologies.
How can you evaluate the spindle apparatus?
Unfortunately, it is impossible to see the structure of microtubules, chromosomes and their division poles through a classical microscope. Only a few clinics have polarizing equipment for imaging the division spindle in germ cells. Because of this, this mitotic component is often not appreciated in routine practice.
The importance of spindle apparatus quality in fertilization
In normal form, the structure is clearly rendered. The spindle of division is located at the polar body, a cell that is detached during the maturation of the oocyte.
There are anomalies here:
- render breaks;
- no spindle.
In conditions without pathologies, the efficiency of conception is 90%, the yield of embryos is 76%. Spindle apparatus anomalies significantly reduce these rates. Thus, the probability of fertilization decreases to 72%, and the yield of embryos – to 31%.
The size of the mitotic structure also matters. With a spindle with an area of 90-120 microns 2 the probability of successful conception is maximum.
ICSI procedure also depends on the assessment of this component. The embryologist’s job is to position the cell correctly. As a rule, the polar body serves as a marker. In order not to damage the spindle located under it during the injection, the specialist orientates the cell at 6 or 12 hours. But this approach is not optimal. Research results have shown that the location of the spindle is not always unambiguous. Therefore, you cannot rely on the theoretical location of the structure.
At the Lada clinic, a preliminary assessment of oocytes is carried out using a special polarizer. This technique allows embryologists to check the location of the chromosomal structure prior to manipulation.