AbstractAt ejaculation sperm cells cannot fertilize. They need to undergo a series of molecular modifications to achieve competency. Surprisingly,molecular markers for identifying sperm populations competent to fertilize are not robust. However, recently an intra - acrosomal protein exposed at the sperm-surface (zonadhesin) has been associated in mouse with the sperm population ready to fertilize (capacitated). Zonadhesin is a sperm protein involved in sperm-ZP adhesion and is located in the acrosome, but is accessible after sperm undergo capacitation.When the sperm population isundergoing capacitation, the number of cells displaying zonadhesin is significantly increased potentially reflecting their fertilizing capacity. The objective of this study is to evaluate this event on human spermatozoa. Apart from zonadhesin, two other acrosomal molecules with a role in sperm-egg interaction, sp56 and sp32,were also studied for potential sperm surface exposure during capacitation.
The first aim was to establish the optimum time of incubation under capacitating conditions for sperm capacitation in vitro. Additional aims of this project were to detect the acrosomal proteins’ forms present in the mature human spermatozoa incubated under capacitating and non -capacitating conditions and compare these protein forms of zonadhesin to those observed in samples from sub fertile men providing preliminary data on their clinical relevance. The study of acrosomal protein exposure at the cell surface by immunofluorescence demonstrated that all three acrosomal molecules were accessible at the sperm surface of cells incubated under capacitating conditions but not of cells incubated under non-capacitating conditions and therefore this event was associated to sperm capacitation.
|Date of Award||2013|
|Supervisor||Christopher Barratt (Supervisor)|