TECHNIQUE

There are two ways to transfer cytoplasm between oocytes. One possibility is to create cytoplasts (cytoplasm packed by cytoplasmic membrane) from donator oocytes. Cytoplasts can be transferred to the interior of zona pellucida of receptor oocytes through a sufficiently big hole. Once in contact with the receptor oocyte cytoplasm, na electric pulse stimulates the fusion between the cytoplams and the cytoplast. Despite the fact that this technique offers high fusion rates, some steps are difficult and, besides, there could be damage to na organelle with hte electrofusion. Other possibility is cytoplasm transfer by microinjection.

In this technique, na appropriate amount of cytoplasm is aspirated from the donator oocyte, with the help of a micropipette, and then injected into the receptor oocyte cytoplasm. This micropipette must be approximately 8 mm thick (in diameter), being essentially similar to the pipette used for ICSI. Moreover, the position of the donator oocyte is important. The polar body must be in the 12 o’clock position, at least, to avoid aspiration of cytoplasm coming from the meiotic spindle region. Cytoplasm transfer from the receptor oocyte must be done with care in order not to damage it and, at the same time, allow positioning the transferred cytoplasm in the appropriate ooplasm region.

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