Relationship between Fertilizing Ability of Ejaculated Human Spermatozoa and Its Chromatin Heterogeneity

OBJECTIVE: The aim of this study was to examine the relationship between the fertilizing ability of ejaculated human sperm and its chromatin heterogeneity. METHOD: We used the D-AO staining method (acridine orange epifluorescence accompanied by diamide, a thiol oxidizing agent) to analyze the sperm chromatin structure of infertile patients with IVF-ET treatment. SDS-PAGE was performed to analyze the sperm nuclear proteins collected from patients with immature sperm (stained red with D-AO staining) and proven fertile men. RESULTS: 1. It was suggested that D-AO staining allowed the immature sperm to be divided into two groups. One was immature sperm, which had disturbance of S-S formation in the epididymides, and the other was sperm that which had an abnormal exchange process of nuclear proteins in the testes. 2. The stainability after D-AO staining showed no correlation with the findings of semen analysis. 3. The fertilization rate of IVF-ET was significantly correlated to the percentage of green sperm staining with D-AO staining. 4. In the pregnant group after IVF-ET, it was noticed that sperm of the green type with D-AO staining was increased in comparison with the non-pregnancy group. 5. The fertilization rate in the group of the sperm stained red with D-AO staining was increased to 73.5% by ICSI. 6. Definite differences were noticed between the protein components of the patients with immature sperm and those of the proven fertile men by analysing with SDS-PAGE. CONCLUSION: D-AO staining was an efficient method for evaluating the fertilizing ability of human ejaculated sperm, and to determine an appropriate ART tool such as ICSI.