Study question

Is it possible to reduce sperm DNA fragmentation index (DFI) by sequential treatment of density gradient centrifugation (DGC) and magnetic-activated cell sorting (MACS)?

Summary answer

Combination treatment of DGC and MACS showed a significant synergy effect on reducing the DFI of semen samples.

What is known already

Density gradient centrifugation is widely used to collect the sperm with progressive motility from the raw semen. Recently, an inverse correlation between sperm DNA fragmentation and progressive motility was observed in our previous studies. MACS recently has been introduced for isolation of non-apoptotic sperm because apoptosis is well known to be a major cause of sperm DNA fragmentation. Although a few of authors reported a positive effects of DGC and MACS on reducing the sperm DFI, further studies need to investigate the effect of combination of DGC and MACS on isolation of the sperm with high DNA integrity.

Study design, size, duration

This is a prospective study performed from Jan. 2015 to Aug. 2015.

Participants/materials, setting, methods

29 normozoospermic semen samples were obtained from the volunteers. Sperm with progressive motility were isolated from raw semen by DGC, and then the motile sperm was separated into apoptotic and non-apoptotic sperm by using MACS ART Annexin V system kit. Sperm DFI was evaluated with Halosperm test.

Main results

Sperm DNA fragmentation index (11.6%) of non-apoptotic sperm was significantly lower than that (21.1%, P<0.01) of apoptotic sperm which means a positive effect of MACS on reducing the sperm DFI. An inverse correlation between sperm DFI and progressive motility was observed in both apoptotic (r=-0.506, P<0.01) and non-apoptotic sperm (r=-0.508, P<0.01). Density gradient centrifugation also significantly reduced the sperm DFI (11.5%) of raw semen down-to 8.1% (P<0.05). The sperm DFI (11.5%) after DGC alone was significantly re-decreased to 4% (P<0.05) after combination treatment of DGC and MACS.

Limitations

The limitation in the number of the semen samples involved in this study which slightly reduced the statistical analysis power.

Wider Implications

This combination treatment will be a practical and efficient method to isolate the sperm with high DNA integrity for the patients who showing high sperm DFI.