Sperm motility and DNA integrity affected by different g‐forces in the preparation of sperm in urine specimens

Retrograde ejaculation, a common type of anejaculation, is attributable to many causes, some of which can be treated with medication and some of which cannot. For infertility treatment, sperm must be collected from the urine of the patients. Our study attempts to ascertain the effects of different g‐forces on sperm motility, morphology and DNA integrity in sperm preparation by the Sil‐Select? density gradient method of isolating sperm from urine specimens. Forty‐seven semen samples with normal semen analyses according to World Health Organisation (WHO) 1999 criteria were included in this study. Semen samples of 1 ml were mixed with 20 ml alkalinised normal urine and then divided equally into tubes A and B. The two samples were prepared by the Sil‐Select? density gradient centrifugation method at 350 g (tube A) and at 700 g (tube B). Total motile sperm after centrifugation at 700 g was significantly higher than after centrifugation at 350 g [6.7 (0.4–23.0) million versus 3.1 (0.1–13.7) million] (P < 0.001). There was no significant difference between the either the percentage of sperm with normal morphology or with DNA damage between centrifugation at 350 g and 700 g (P > 0.05), although centrifugation at 700 g achieves a higher number of total motile sperm compared with Sil‐Select? sperm preparation at 350 g centrifugation.