Ovum Activation with Calcium Ionophore Method in Insemination Failures Based on Sperm Defects

In order that the ovum is inseminated by the sperm, the sperm should penetrate through the external membrane of the ovum and leave its genetic material. The sperm penetrates into the ovum by the help of some enzymes in the acrosome area which enables it to penetrate through the ovum membrane by melting the external membrane of the ovum. Thus, ovum activation which is required for insemination is sitmulated. The most important process in the activation of the ovum is the increase in the amount of calcium within the ovum. As a result of these events, sperm penetrates into the ovum and inseminates the ovum.

In the studies, it was observed that sperm plays an important role in ovum activation. In patients who suffer severe sperm problem (number, movement disorders and structural defects), especially in Globozoospermi cases (lack of acrosome structure in the head), unfertilization may occur at the rate of 20-30% in ova in which ICSI (microinjection) is applied. It was determined that DNA fragmentation is high in sperms with these phenomena. This also causes decrease in the insemination rates. In addition, insemination is not observed in any of the ova in which ICSI is applied in 1-5% cycle. Different methods are used in order to prevent this condition, which is called as total insemination failure. Calcium ionophore, one of these methods, increases the amount of calcium within the cell after ICSI (microinjection) and increases the ovum activation.

The sperm which will realize insemination excretes oscilin, which is a solvent, after sticking to oocyte membrane. Thus the transmission of the calcium ions is realized and oocyte is activated. Similarly, a phospholipase, called a sperm specific PLC zeta factor, is another material which stimulates the calcium oscillation within the cell and enables oocyte activation and completion of meiosis of the oocyte. Since globozoospermi patients lack acromosal area and oocyte activator, calcium transmission is activated using calcium ionophore. Thus, oocyte activation is realized.

Calcium ionophore is not routinely available in embryo culture medium. It is added to the culture medium with a special method and activation of ova is enabled. In scientific studies, it was seen that activating the ovum chemically increases insemination rates from 20,6% up to 46,7% and pregnancy rates from 13,9% up to 27,7% (Montag et al.). Thus, despite defects based on sperm and ovum, it is possible to achieve increase in pregnancy and live birth rates.

 At our center, we achieve significant success by increasing both impregnancy rates and pregnancy and live birth rates using Calcium Ionophore method in cases where impregnancy is not available or delayed.