Variance in total levels of phospholipase C zeta (PLC-ζ) in human sperm may limit the applicability of quantitative immunofluorescent analysis as a diagnostic indicator of oocyte activation capability

Objective: To examine whether similar levels of phospholipase C zeta (PLC-zeta) protein are present in sperm from men whose ejaculates resulted in normal oocyte activation, and to examine whether a predominant pattern of PLC-zeta localization is linked to normal oocyte activation ability. Design: Laboratory study. Setting: University laboratory. Patient(s): Control subjects (men with proven oocyte activation capacity; n = 16) and men whose sperm resulted in recurrent intracytoplasmic sperm injection failure (oocyte activation deficient [OAD]; n = 5). Intervention(s): Quantitative immunofluorescent analysis of PLC-zeta protein in human sperm. Main Outcome Measure(s): Total levels of PLC-zeta fluorescence, proportions of sperm exhibiting PLC-zeta immunoreactivity, and proportions of PLC-zeta localization patterns in sperm from control and OAD men. Result(s): Sperm from control subjects presented a significantly higher proportion of sperm exhibiting PLC-zeta immunofluorescence compared with infertile men diagnosed with OAD (82.6% and 27.4%, respectively). Total levels of PLC-zeta in sperm from individual control and OAD patients exhibited significant variance, with sperm from 10 out of 16 (62.5%) exhibiting levels similar to OAD samples. Predominant PLC-zeta localization patterns varied between control and OAD samples with no predictable or consistent pattern. Conclusion(s): The results indicate that sperm from control men exhibited significant variance in total levels of PLC-zeta protein, as well as significant variance in the predominant localization pattern. Such variance may hinder the diagnostic application of quantitative PLC-zeta immunofluorescent analysis. (Fertil Steril (R) 2013; 99: 107-17. (C) 2013 by American Society for Reproductive Medicine.)