PERCOLL GRADIENT CENTRIFUGATION CAN BE OMITTED IN SPERM PREPARATION FOR INTRACYTOPLASMIC SPERM INJECTION

Prior to intracytoplasmic sperm injection (ICSI), seminal fluid is cur rently washed out from the ejaculated semen and further sperm selectio n is carried out by a discontinuous Percoll gradient, Possible deleter ious effects from the sperm-separating substance Percoll on sperm func tion or embryo cleavage after in-vitro fertilization (IVF) have, to ou r knowledge, not yet been reported and the use of Percoll has been wid ely accepted in IVF, In this study, we examined whether the omission o f the Percoll step in the sperm preparation has any influence on the o utcome of the ICSI procedure, Two methods of sperm preparation for ICS I were compared in a controlled study on sibling oocytes: washing the semen sample once, followed by a Percoll gradient centrifugation versu s washing the sperm sample twice without a Percoll gradient centrifuga tion, The mean fertilization rates were similar for the two sperm prep aration methods: 78.2 +/- 21.4 and 75.0 +/- 24.1% respectively of the intact oocytes displaying two pronuclei, Cleavage rates did not differ statistically between the two groups, Whereas in both groups similar percentages of excellent, good and poor quality embryos were obtained, the percentage of fair quality embryos was significantly higher in th e group without Percoll (16.3 +/- 20.1 versus 9.1 +/- 15.7%), However, no statistical differences were observed in either the percentage of transferable embryos or in the percentage of embryos actually transfer red or frozen in the two groups, In conclusion, spermatozoa from ejacu lates that are washed out from the seminal fluid without any further s election can be used for ICSI without any adverse effect on fertilizat ion and embryo cleavage.