Assessment of density gradient centrifugation (DGC) and sperm chromatin dispersion (SCD) measurements in couples with male factor infertility undergoing ICSI.

PURPOSE

To investigate how effectively density gradient centrifugation (DGC) improves sperm nuclear integrity and to determine whether the sperm chromatin dispersion (SCD) test of sperm nuclear integrity in native or DGC-treated semen can predict the outcome of assisted reproductive technology (ART) in couples undergoing intracytoplasmic sperm injection (ICSI).

METHODS

The DNA integrity of spermatozoa from 63 male factor infertility patients undergoing ICSI was analyzed by the SCD test before and after DGC. The predictive value of the sperm DNA fragmentation index (DFI) for ART outcomes was assessed in a cohort of 45 patients who were undergoing fresh embryo transfer. For the analysis, they were divided into pregnant and non-pregnant groups and, independently, into high sperm DFI (DFI > 30%) and low sperm DFI (DFI ≤ 30%) groups. Both raw and DGC semen parameters were examined.

RESULTS

In the asthenospermia and oligozoospermia groups, DGC decreased the sperm DFI from 31.5 ± 19.7 and 28.5 ± 10.3 to 19.2 ± 18.3 and 16.0 ± 12.8, respectively (P < 0.01). DGC decreased the sperm DFI in the severe oligozoospermia group from 41.4 ± 19.0 to 36.3 ± 20.6 (P > 0.01). The pregnant and non-pregnant groups did not differ in their fertilization rate and sperm DFI in native or DGC semen (P > 0.05). There was also no significant difference between the high sperm DFI (DFI > 30%) and low sperm DFI (DFI ≤ 30 %) groups with regard to fertilization rate, implantation rate, and clinical pregnancy rate for both native and DGC semen (P > 0.05). The patients undergoing ICSI with a high sperm DFI had a higher pregnancy loss rate (defined as spontaneous miscarriage or biochemical pregnancy) compared with patients with a low sperm DFI in both the native and DGC semen groups.

CONCLUSIONS

DGC highly significantly reduces sperm DNA fragmentation in the semen of ICSI patients, with the exception of those with severe oligozoospermia. The results of the SCD test of sperm DNA fragmentation in native or DGC semen do not correlate with the fertilization rate, implantation rate, or clinical pregnancy rate in patients undergoing ICSI.