Intracytoplasmic sperm injection: method and application in veterinary science

Intracytoplasmic sperm injection is the newest and the most successful micromanipulation technique for treating male factor infertility. It entails the mechanical insertion of a chosen spermatozoon directly in to the cytoplasm of an oocyte. The technique was used in veterinary science for the purpose of clarifying the different steps of fertilization by investigating the fusion and penetration of animal gametes. First mammalian egg injection procedure was reported by Lin (1966). Later Uehra and Yanagimachi (1976) described the microinjection of human and golden hamster spermatozoa into hamster eggs. Hosoi et al (1998) obtained live offspring after transfer of micro fertilized rabbit eggs into the oviduct of pseudo pregnant female rabbits. Based on the successful fertilization of normal animal gametes using ICSI, the procedure was experimentally applied to human gametes. In the veterinary field micromanipulation of murine and domestic animal species has been used for the past two decades both as an experimental tool and in the commercial field. The focus of the commercial field has largely been on developing and refining the cloning technology and production of transgenic animals. The use of micromanipulation technique to enhance fertilization in domestic animals has not been developed because fertilization is rarely a problem. In humans, however one in six couples has fertility problems and male factor components are responsible for one third of infertile couple.