In vitro sperm binding penetration

Journal of in Vitro Fertilization and Embryo Transfer. The structure of the zona pellucida and the early interactions between human oocytes and spermatozoa were investigated in an in vitro fertilization program. Thirty-five mature preovulatory oocytes, 10 immature oocytes lacking a germinal vesicle, and 11 atretic oocytes which had not undergone fertilization at 10—20 hr after insemination were studied by light and scanning electron microscopy. The smooth-surfaced zona was most commonly seen in the cultured oocytes belonging to the immature and atretic groups. These observations seem to show that the spongy appearance of the zona pellucida is related mainly to oocyte development and maturity. In this study, greater numbers of penetrating spermatozoa were noted on oocytes showing the mesh-like zona, in contrast to the presence of a few sperm flattened against its surface or the frank absence of sperm associated with oocytes having the more compact, smooth zona.

Sperm-zona binding, sperm-oocyte penetration and pronucleus formation in oocytes obtained after in-vitro fertilization IVF failure were studied by analysing DNA fluorescence. Oocytes were classified according to their maturational status, sperm-zona pellucida binding and sperm-oocyte penetration. Spermatozoa were classified as normal or abnormal according to conventional parameters. Sperm-zona binding and sperm-oocyte penetration into uncleaved oocytes were positively related to fertilization: 6. When at least one oocyte per cohort fertilized, these rates were

Sperm capacitation and in vitro fertilisation IVF have been achieved in most eutherian mammals and American marsupials under relatively simple culture conditions. In contrast sperm capacitation in Australian marsupials has not been achieved in vitro and attempts at IVF have previously been characterised by a complete lack of sperm-zona pellucida ZP binding. Recently, co-culture of sperm with oviduct epithelial cell monolayers or with oviductal explant conditioned media has been shown to prolong the viability and motility of brushtail possum spermatozoa, as well as to induce capacitation-associated changes such as transformation of sperm to the T-shape orientation. Development of ZP receptivity and penetrability towards sperm was also identified as a major factor affecting the outcome of IVF. Neither in vivo nor in vitro derived T-shaped sperm were able to bind to or penetrate the ZP if eggs were obtained from animals that were treated with pLH less than 76 h after PMSG.

Fertilization occurs when a sperm and an oocyte egg combine and their nuclei fuse. Because each of these reproductive cells is a haploid cell containing half of the genetic material needed to form a human being, their combination forms a diploid cell. This new single cell, called a zygote , contains all of the genetic material needed to form a human—half from the mother and half from the father. Fertilization is a numbers game.