Induction of fertilization by intrapronuclear male gameteinjections into oocyte pronucleus

2000 Fiscal Year Final Research Report Summary

• Project/Area Number: 11671554
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Urology
• Research Institution: Tottori University
• Principal Investigator: NIKOLAOS Sofikitis Department of Urology, Faculty of Medicine , Tottori University, Assistant Professor, 医学部・附属病院, 講師 (60252863)
• Co-Investigator(Kenkyū-buntansha): YASUHISA Yamamoto Department of Urology, Faculty of Medicine, Tottori University, Research Associate, 医学部, 助手 (00294314)
• Project Period (FY): 1999 – 2000
• Keywords: oocvte / sperm / pronuclei / fertilization

Research Abstract

Oocyte activation, sperm head decondensation within the ooplasm, transformation of the male gamete nucleus into the pronucleus and pronuclei fusion are the last steps of the fertilization process. failure in one of the above interactions between the male and the female gamete results in ICSI failure. We investigated the possibility of bypassing the last events of the fertilization process by injecting a pre-decondensed or preactivated oocytes.
We evaluated the development of rat preactivated oocytes after intrapronuclear pre-decodensed sperm head injections (IPSHIs). maturn rat oocytes received a combination of electrical and chemical stimulation or a combination mechanical and chemical stimulation. Activated oocytes were treated with IPHSI.A pre-decondensed sperm head was injected into the larger female pronucleus of eac oocyte. In addition, a piece of sperm tail was left near the outer surface of the injected pronucleus.
Events that followed IPSHI techniques were : a visible sperm head within the pronucleus ; swelling of the pre-decondensed sperm head within the pronucleus ; an invisible sperm head within the pronucleus ; enlargement of the pronucleus ; and first cleavage in process.
Rat IPSHI techniques result in syngamy, mitotic division of zygote. Successful performance of IPSHI techniques may be a novel method to manage cases of ICSI failure due to either a lack of development of the male pronucleus of failure in pronuclei fusion.