Assessment of Expression Levels and Localization Patterns of Phospholipase C zeta (PLC-ζ) in Different Grades of HOST in Human Sperm

Document Type : Original Article


1 Faculty of Medicine, Kurdistan University of Medical Sciences, Sannandaj, Iran.

2 Department of Midwifery, Falavarjan Branch, Islamic Azad University, Isfahan, Iran



Background: PLC-ζ deficiency in sperm can underlie oocyte activation failure after ICSI. The aim of this study was to determine PLC-ζ expression and location in individual spermatozoa in each host score so that a hypo-osmotic swelling test (HOST) may be used to help routine sperm selection for ICSI.

Materials and Methods: In this Experimental study, Fresh semen samples were randomly obtained from 30 men who were referred to the Andrology Unit of the Infertility Center. Samples were processed by density gradient and exposed to hypotonic conditions. Seven different tail patterns, classified from 'a' to 'g' can be detected according to WHO criteria. Then, PLC-ζ protein localization pattern was assessed by quantitative Immunofluorescence in individual sperm Host grades. Moreover, the sperm content of PLC-ζ protein was evaluated by flow cytometry correlated with semen analysis parameters.

Results: In the present study, quantitive immunofluorescence analysis indicated that sperm from different host grades exhibited seven localization patterns of PLC-ζ of acrosomal (A); equatorial (EQ), and postacrosomal (PA) patterns. A + EQ = acrosomal and equatorial, A+PA= acrosomal and post-acrosomal, EQ+PA = equatorial and post-crosomal, and A + EQ + PA.

The sperm from HOST grade 'd' exhibited significantly higher PLC-ζ (A+PA) and (A+EQ+PA) staining compared to sperm from other grades (P = 0.006). The sperm from grade 'd' exhibited higher PLC-ζ (EQ +PA) compared with other grades (P = 0.001). However, grade 'd' was not significantly different from 'c' (P=.087). Analysis of the combined results confirmed that there was a clear reduction in PLC-ζ immunofluorescence in Host grades 'a', 'f' and 'g' sperms.

Conclusion: Our data suggest that HOST may represent a useful diagnostic tool for the selection of sperms exhibiting a higher level of PLC-ζ expression.

Keywords: Phospholipase C Zeta, Hypo Osmotic Swelling Test, Infertility, Intracytoplasmic Sperm Injection, Oocyte Activation


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