Combination of density gradient centrifugation and swim-up methods effectively decreases morphologically abnormal sperms

Abstract

Density gradient centrifugation (DGC) and swim-up techniques have been reported for semen preparation in assisted reproductive techniques in humans. We investigated whether semen preparation using a combination of DGC and swim-up techniques could effectively decrease morphologically abnormal human sperms at the ultrastructural level. Semen samples were obtained from 16 infertile males and fractionated by swim-up following DGC. Ultrastructural abnormalities of sperms obtained from original semen, lower layer of swim-up following DGC, and upper layer of swim-up following DGC were analyzed by transmission electron microscopy. The correlation among ultrastructural head abnormality in sperms from the upper layer of swim-up, fertilization in in vitro fertilization, and pregnancy after embryo transfer was also investigated. Furthermore, sperms with DNA fragmentation in the samples processed via a combination of DGC and swim-up was assessed in a sperm chromatin structure assay. Ultrastructural abnormalities in sperm heads and tails in the upper layer after swim-up following DGC was the lowest among the three groups. Sperms with nuclear vacuoles were the most difficult to eliminate using a combination of DGC and swim-up in all types of head abnormalities. A negative correlation was confirmed between the fertilization rates of intracytoplasmic sperm injection and head abnormality of sperms obtained from the upper layer of the swim-up following DGC. Sperms with DNA fragmentation were effectively decreased using the combination of two techniques. In conclusion, the combination of DGC and swim-up effectively decreased the number of sperms with ultrastructural abnormalities both in the head and in the tail. However, sperms with ultrastructural abnormalities that cannot be completely decreased using a combination of DGC and swim-up may impair fertilization in some cases of intracytoplasmic sperm injection.

A comparative evaluation of migration sedimentation method for sperm preparation

“…A recent publication revealed significantly enhanced morphology of sperm, selected by the combination of DSG+SU [Yamanaka et al 2016]. Our study, using normozoospermic samples, presents comparable outcomes after MS, compared to the combination of DGC and SU (10.67±5.44% vs. 12.19±6.45%, respectively, p=0.220) (Table 2; Figure 2).…”

“…Density gradient centrifugation, (DGC) allows elimination of the leukocytes, immature or damaged spermatozoa, spermatogenic cells, infectious agents, epithelial cells, and seminal plasma, where most are expected to stay suspended on the upper layers of the solutions after centrifugation [Michou et al 2012]. The pelleted cohort represents improved morphology [Yamanaka et al 2016], motility [Noguchi et al 2015], and nuclear content [Amiri et al 2012;Matsuura et al 2010;Muratori et al 2016]. A subsequent sperm selection method, called the swim-up technique (SU) is usually used in combination with DGC for the selection of the most active and motile spermatozoa [Mortimer 1994;Volpes et al 2016;WHO 2010].…”

Direct swim-up without centrifugation is a more recommended technique for sperm preparation in conventional IVF cycles

“…For this combination technique, swim-up procedure was performed after the elimination of harmful components by density-gradient centrifugation. DGC-SU has been reported to be favorable for sperm preparation in IVF cycles, as spermatozoa prepared by this technique were found to have higher rates of motility and reduced DNA fragmentation compared with other procedures [4][5]22].…”

“…However, several studies reported that a combination technique of density-gradient centrifugation and swim-up (DGC-SU) was more effective in enriching sperm cells with normal morphology and eliminating sperm cells with DNA fragmentation than DGC technique alone [4][5][6][7]. Given this, the DGC-SU technique is more widely used in the field of ART work concerning sperm preparation compared to DGC technique alone at the present time in China.…”

Sperm enrichment from poor semen samples by double density gradient centrifugation in combination with swim-up for IVF cycles

“…However, studies from different groups have drawn inconsistent conclusions [1][2][3][4][5][6] . Recent studies have suggested that DGC in combination with SU (DGC/SU) could be one of the most effective approaches 7,8 . Most Chinese reproductive centres, including ours, have adopted DGC/SU for enriching sperm in IVF.…”