The role of sperm factors involved in oocyte activation and fertilization

Background: Failed fertilization post intra-cytoplasmic sperm injection (ICSI) has been mainly attributed to the sperm’s inability to induce oocyte activation. This phenomenon may account for about 30% of human oocytes that fail to fertilize following ICSI and 2–3% of complete fertilization failure following ICSI. PLCζ (Phospholipase C zeta), PAWP (Post-acrosomal WW-domain binding protein) and TR-KIT (Truncated form of KIT) are suggested as main sperm factors for the induction of oocyte activation. The aim of this study was to compare PLCζ, PAWP and TR-KIT between infertile men with globozoospermia and men with failed fertilization post-ICSI with fertile individuals at sperm RNA and protein molecules level. In addition, localization of these sperm factors also was determined.Methods: In this study, semen samples were collected from 50 infertile men with failed fertilization post ICSI, 30 globozoospermic men and 30 fertile men. Sperm parameters (concentration, motility, morphology) were assessed according to World Health Organization (2010) and Real-time PCR, Western blot and immunofluorescence techniques were used for assessment of RNA, protein, and localization of PLCζ, PAWP and TR-KIT, respectively.Result: Mean expression of sperm PLCζ, PAWP and TR-KIT at RNA and protein level were significantly lower in infertile men with globozoospermia and men with failed fertilization post-ICSI compared to fertile individuals. These factors mostly were observed in equatorial region of sperm head.Conclusion: The result of this study, for the first time, suggested that all three sperm factors involved in oocyte activation significantly decreased in infertile individuals with failed fertilization ICSI and globozoospermic individuals compared to fertile men at RNA and protein. In addition, localization of all three sperm factors were detected in equatorial of sperm head, where fusion of sperm and oocyte occur. Therefore, assessment of expression of PLCζ, PAWP and TR-KIT were consideredas useful markers for the ability of sperm to induce oocyte activation .

کلیدواژه ها:

Globozoospermia ، PAWP ، PLCζ ، TR-KIT ، Fertilization