Predictive value of chromatin decondensation in vitro on fertilization rate after intracytoplasmic sperm injection (ICSI)

This study was undertaken to identify the relationship between sperm chroma tin decondensation after incubation with sodium dodecyl sulphate (SDS) and ethylene diamine tetra acetic acid (EDTA), or heparin at various points of time. Likewise, this study will determine chromatin stability within defini te time intervals, chromatin decondensation after intracytoplasmic sperm in jection (ICSI), and whether chromatin decondensation in vitro could be used as a predictive test for fertilization capability after ICSI. Sixty-five i nfertile couples undergoing ICSI therapy were included in this prospective study. Male factor infertility was the main indication for inclusion. One m illilitre from each semen sample after washing was mixed with SDS-EDTA (gro up 1) or SDS/heparin (group 2) and incubated for 120 min. Many smears were made within 10 min of mixing the spermatozoa with detergent and the reducin g agents and at the following points of time 30, 60 and 120 min and after 2 4 h. Chromatin decondensation was evaluated after staining with acridine or ange (AO). The mean percentage of uncondensed chromatin of spermatozoa in t he semen sample in the first group before addition of SDS/EDTA was 26.1 +/- 19.0 and 22.3 +/- 18.9% in the second one. After incubation of spermatozoa for 30, 60 and 120 min and 24 h, the chromatin decondensation increased in the first group to 64.0 +/- 28.6, 83.0 +/- 21.1, 87.9 +/- 14.6, 92.1 +/- 1 6.2 and 98.0 +/- 6.75%, respectively. The corresponding values in the secon d group were 69.5 +/- 29.9, 78.6 +/- 22.4, 86.9 +/- 17.1, 95.13 +/- 6.5 and 98.3 +/- 5.6%. On the other hand, no correlations were found between the c hromatin decondensation or chromatin decondensation rate in vitro and the f ertilization rates in all investigated groups. In conclusion, neither the c hromatin decondensation ability in vitro nor the rate of chromatin deconden sation between various points of time after using SDS/EDTA, SDS/heparin cou ld predict the chromatin decondensation of spermatozoa (fertilization capab ility) after ICSI.