Functional analyses of the sperm centrosome in human reproduction: implications for assisted reproductive technique.

Although intracytoplasmic sperm injection (ICSI) is an innovative treatment for male infertility, a significant number of clinical cases of fertilization failure remain. ICSI overcomes the difficulty during fertilization of spermatozoon entry into the egg cytoplasm. The goal of fertilization, however, is the union of the male and female genomes; spermatozoon incorporation into the oocyte is only the initiation of fertilization. During fertilization in most mammalian species, including humans, the spermatozoon introduces the centrosome, which acts as a microtubule organizing center (MTOC). By promoting pronuclear apposition and mitotic spindle formation, the spermatozoon plays the leading part in the induction of "motility" post-ICSI in fertilization. The present review introduces the remaining challenges in functional assessment of the human sperm centrosome and discusses the biparental (for example, rabbit) and maternal (for example, parthenogenesis) centrosomal contributions to microtubule organization during development.