Full-term Development of Hamster Embryos Produced by Injecting Freeze-dried Spermatozoa into Oocytes

Abstract

Abstract: Although injected freeze-dried hamster spermatozoa can develop into male pronuclei even after 12 months of storage at 4°C, the developmental competence of hamster pronuclear oocytes is not well understood. Furthermore, production of live offspring from freeze-dried spermatozoa is limited in some animals, such as mice, rabbits and rats. Here, we report the birth of hamster offspring following intracytoplasmic injection with freeze-dried spermatozoa. The integrity of the sperm DNA after freeze-drying and rehydration is very important for the developmental competence of hamster embryos produced by injecting freeze-dried spermatozoa into oocytes. This study used the TUNEL method to examine DNA fragmentation and the chromosomal integrity of spermatozoa after freezedrying using two freezing media: M2 medium, and a TrisHCI buffered solution containing 50 mM EGTA (EGTA solution). The rate of DNA fragmentation when hamster spermatozoa freeze-dried in EGTA solution was used was significantly (P < 0.05) lo...