The essential role of ooplasm in maturing and activating oocytes and in the primary stages of embryonic division is well documented; however, little is known about the details of this process. Cohen et al. (1997) first reported successful human impregnation after transferring the cytoplasm of the donated oocytes to those of the infertile women. Their objective was to restore the normal growth of high-risk oocytes caused by ooplasmic defect. They also reported the birth of over 30 healthy babies by the end of 2004 by the direct injection of the cytoplasm from donated (either frozen or fresh) oocytes to defective ones using modified ICSI. This technique includes the injection of 10-15% of the cytoplasm from a donated oocyte to a target oocyte in order to enhance its genesis under laboratory conditions.The cytoplasm of a mature oocyte can lead to the maturity of a defective oocyte, due to having regulators of cell cycle, healthy mitochondria, microtubules involved in cell division, DNA replication enzymes, and enhancing the level of mRNA.
This technique can be used for women who have had repeated IVF failure or unsuccessful implantation due to poor quality embryos in their previous cycles.
According to the studies conducted on the expression levels of genes involved in the natural trend of development and evolution of human oocyte, the present study aims to evaluate the changes in the expression of genes that occur in an oocyte after cytoplasmic injection and compare its results to the oocytes in the control group. It is noteworthy that the present study will be conducted on available oocytes whose usage will not pose any ethical considerations, including donated and immature oocytes.
In the present work, immature oocytes will be categorized into two categories:
1- 30 immature oocytes as the intervention group: 15% cytoplasm in injected to them; afterwards, they will be cultivated in G1 medium culture and kept in incubator for 24 hours. Then, Trizol solution will be added to them and they will be kept at -80 °C.
2- 60 immature oocytes as the control group, which itself is further categorized into two groups:
a. 30 immature oocytes will be put in the Trizol solution immediately after pick up, and will be kept at -80 °C.
b. 30 immature oocytes will be cultivated in in G1 medium culture and kept in incubator for 24 hours. Then, Trizol solution will be added to them and they will be kept at -80 °C.
After the sampling, the oocytes in each group will be pooled separately. Then, their RNA will be extracted and cDNA will be synthesized. Finally, the expression level of target genes will be determined using the Q RT-PCR in each group.
The level of morphological changes in the oocytes of each group (both intervention and control) will also be determined after 24 hours of incubation using inverted microscope.