Sperm-mediated oocyte activation critically depends upon appropriate expression and assembly of sperm-borne oocyte-activating factors (SOAFs) during spermiogenesis. Several factors have been considered as candidate for SOAFs over the recent years. However, little is known about the expression profile of these candidates and their potential contribution to the clinical outcomes of intra-cytoplasmic sperm injection (ICSI), particularly in globozoospermia. This study investigated the expression profile of PLCζ, PAWP, and TR-KIT and clinical outcomes of ICSI in 12 men with total globozoospermia and compared with 12 fertile individuals. Levels of PLCζ, PAWP, and TR-KIT mRNA in the spermatozoa of fertile men were significantly higher than the corresponding values of the globozoospermic subjects. Interestingly, at protein level, expressions of these factors in the cases assessed were low in globozoospermic individuals. Fertilization rates following artificial oocyte activation (AOA) in the majority of globozoospermic couples were higher than the expected 30% cut-off value reported for individuals with failed or low fertilization rate. Clinical outcomes of ICSI-AOA were dependent on inter-individual variation in globozoospermic couples. None of the SOAFs assessed could provide a greater prediction value with respect to fertilization rate in globozoospermic couples which underwent ICSI-AOA. High fertilization (56.06%) and pregnancy (41.7%) rates accomplished in this study following ICSI-AOA indicated that expression profiles of PLCζ, PAWP, and TR-KIT were low in globozoospermic individuals, and ICSI combined with artificial oocyte activation could mimic physiological calcium changes which occur during fertilization.
Keywords: PAWP; PLCζ; TR-KIT; fertilization; globozoospermia; pregnancy.
© 2016 American Society of Andrology and European Academy of Andrology.