Fluorescein isothiocyanate conjugate-wheat germ agglutinin staining of human spermatozoa and fertilization in vitro
Objective: To determine the sensitivity and clinical significance of fluorescein isothiocyanate wheat germ agglutinin (FITC-WGA) staining of human spermatozoa. Design: Percentage FITC-WGA staining was assessed in the different morphological zones of human spermatozoa and compared with fertilization rates of metaphase II oocytes in vitro. Patients: Spermatozoa and oocytes were obtained from normospermic (n = 12) and male factor patients (n = 15) attending the Tygerherg Hospital's IVF clinic. Main Outcome Measures: Aliquots of swim-up spermatozoa used in the IVF laboratory were examined for the presence and morphological localization of WGA receptors. Fertilization rates were expressed as the percentage of metaphase II oocytes with successful fertilization. Results: Human spermatozoa capacitated in vitro for use in an IVF program showed variations in the percent positive staining of the acrosomal region which correlated with IVF rates in both patient groups studied. Values of FlTC-WGA acrosomal staining of <37% corresponded with IVF rates of <50% whereas >35% WGA acrosomal staining corresponded with IVF rates ≥50%. Significant differences between acrosomal and equatorial region staining from normozoospermic samples and male factor samples also were observed. Conclusion: The results indicate the practical use of the WGA assay for molecular assessment of male fertilizing capacity in conjunction with an assisted reproductive program.