Expression profile ofPLCζ,PAWP,andTR-KITin association with fertilization potential, embryo development, and pregnancy outcomes in globozoospermic candidates for intra-cytoplasmic sperm injection and artificial oocyte activation

Abstract

SUMMARYSperm-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 PLCf, PAWP, and TR-KIT and clinical outcomes of ICSI in 12 men with total globozoospermia and compared with 12 fertile individuals. Levels of PLCf, 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 PLCf, 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.

An association between sperm PLCζ levels and varicocele?

“…In the light of these considerations, we also showed that expression level of PLCζ mRNA were significantly lower in infertile men with previous failed fertilization and globozoospermia than fertile individuals [12]. Other researchers also observed the absence or low expression of PLCζ protein in infertile men with globozoospermia and concluded that this factor could be considered as a prognostic marker of oocyte activation [12,18,20]. Recent studies have demonstrated that sperm factors involved in oocyte activation are sensitive to heat treatment or cold shock during freeze-thawing [21,22].…”

“…Densitometric analysis of the images was performed by Quantity One Software v 4.6.9 (Bio-Rad, Munchen, Germany). Results were expressed as mean relative intensity [20].…”

Globozoospermia syndrome: An update

“…Successful ART outcomes by resorting to some new treatment protocols/techniques along with ICSI, such as ICSI with AOA using calcium ionophore, may help overcome male infertility in patients with total globozoospermia (Abadi, Tavalaee, Shahverdi, & Nasr‐Esfahani, ; Karaca et al, ; Kochhar & Ghosh, ; Shang et al, ; Tavalaee et al, ). Some candidate genes such as truncated Kit, PLC ζ and post‐acrosomal sheath WW domain‐binding protein (PAWP) are found to be responsible for oocyte activation during fertilisation (Abadi et al, ; Haghighat et al, ; Tavalaee & Nasr‐Esfahani, ). Significantly lower expression profiles of these genes and their corresponding proteins in globozoospermic men have been reported, suggesting a beneficial effect of AOA resulting in higher fertilisation rates after conventional ICSI (Abadi et al, ; Haghighat et al, ; Tavalaee & Nasr‐Esfahani, ; Taylor et al, ).…”

Association between total globozoospermia and sperm chromatin defects

“…Fertilisation failure by round‐headed sperm after ICSI can be mainly attributed to deficiency or absence of sperm factors, which are essential for oocyte activation. In this regard, several studies indicate that expression of sperm‐specific phospholipase C (PLCζ) as a major sperm oocyte‐activating factor were very low or absent in round‐headed sperm in comparison with normal sperm (Amdani, Jones, & Coward, ; Chansel‐Debordeaux, Dandieu, Bechoua, & Jimenez, ; Kamali‐Dolat Abadi, Tavalaee, Shahverdi, & Nasr‐Esfahani, ; Tavalaee & Nasr‐Esfahani, ; Taylor et al.,). Moreover, thirteen genes are known to be involved in acrosome biogenesis process and possibly their deficiency can be detected in round‐headed sperm.…”