Combination of density gradient centrifugation and swim-up methods effectively decreases morphologically abnormal sperms.
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.
IVF Namba Clinic, Osaka 550-0015, Japan.
Masaya
M
Yamanaka
Kazuhisa
K
Tomita
Shu
S
Hashimoto
Hiroshi
H
Matsumoto
Manabu
M
Satoh
Hiromi
H
Kato
Yoshihiko
Y
Hosoi
Masayasu
M
Inoue
Yoshiharu
Y
Nakaoka
Yoshiharu
Y
Morimoto
D000328:Adult; D048430:Cell Shape; D002499:Centrifugation, Density Gradient; D053938:DNA Fragmentation; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D046529:Microscopy, Electron, Transmission; D011247:Pregnancy; D018873:Pregnancy Rate; D027724:Reproductive Techniques, Assisted; D055101:Semen Analysis; D013094:Spermatozoa / Q000166:cytology* / Q000648:ultrastructure