Development of normal offspring from oocytes injected with freeze-dried spermatozoa
AssigneeUniversity of Hawaii
InventorsTeruhiko Wakayama, Ryuzo Yanagimachi
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Abstract
The invention provides a method for freeze-drying spermatozoa to obtain at least one reconstituted spermatozoon whose head (nucleus) is capable of fertilizing an oocyte to produce a live offspring. The motility of spermatozoa which have been freeze-dried and stored in a vacuum at room temperature is not restored when rehydrated. Their plasma membranes are disrupted and they are all “dead” in the conventional sense. However, when they are injected microsurgically into oocytes, their nuclei transform into male pronuclei and participate in normal embryonic development.
Claims29
A membrane-damaged freeze-dried spermatozoon or freeze-dried spermatozoon head, having a moisture content of less than 1% and comprising a nucleus that has retained genetic integrity, wherein after rehydration and insertion of the nucleus into an isolated oocyte, the nucleus fertilizes the oocyte, and the retained genetic integrity of the nucleus is sufficient to result in the development of an embryo and the production of a live offspring.
A method for freeze-drying spermatozoa or isolated spermatozoa heads to obtain a freeze-dried spermatozoon nucleus that retains genetic integrity sufficient to produce a live offspring, after rehydration and insertion of the nucleus into an isolated oocyte, comprising the steps of:
- collecting live spermatozoa;
- optionally isolating spermatozoa heads from the spermatozoa;
- suspending the spermatozoa or spermatozoa heads in a physiological suspension medium;
- freezing the suspension of spermatozoa or spermatozoa heads to form frozen spermatozoa or frozen spermatozoa heads;
- drying the frozen spermatozoa or frozen spermatozoa heads to a moisture level of less than 1% to form freeze-dried spermatozoa having damaged membranes or freeze-dried spermatozoa heads,
- wherein at least one membrane-damaged freeze-dried spermatozoon or freeze-dried spermatozoon head comprises a nucleus that has retained genetic integrity, wherein after rehydration and insertion of the nucleus into an isolated oocyte, the nucleus fertilizes the oocyte, resulting in the development of an embryo and the production of a live offspring.
Dependencies are inferred from the claim text.