Assessment of human sperm protein tyrosine phosphorylation by immunocytochemistry in a clinical andrology laboratory. Preliminary data

Abstract

We propose that evaluation of protein tyrosine phosphorylation (TP) status in ejaculated spermatozoa under capacitating conditions in an experiment that mimics “in vitro” the physiology of sperm from ejaculation through the female genital tract could potentially be used as a prognostic test for functional competence of sperm in fertilization. Our purpose was to elucidate whether there is a relation between conventional sperm parameters, occurrence of TP and pregnancy outcome obtained from intrauterine insemination (IUI). Semen samples were analyzed according to WHO criteria. TP levels were determined by immunocytochemistry under four different conditions: 1) ejaculated sperm, 2) postselection sperm, 3) postselection sperm incubated 5 h at 37° C and 5% CO₂, and 4) postselection sperm incubated overnight at 37° C and 5% CO₂. Data on sperm tyrosine phosphorylated proteins did not correlate with sperm concentration, progressive motility or normal sperm morphology. TP increased under capacitating conditions and showed a time dependent pattern except for five outlier cases. IUI was performed in 12 selected couples who had neither female nor male infertility factors. The three pregnancies had a time dependent pattern for TP. Of the unsuccessful cases, one had an outlier TP pattern. It appears that a TP time dependent pattern is necessary for fertilization.

Key words::

• clinical assays
• fertilization
• immunocytochemistry
• signal transduction
• sperm physiology
• tyrosine phosphorylated proteins

Acknowledgements

This work was supported by grant B031 from University of Buenos Aires Science and Technology (UBACYT).