Rf. Casper et al., THE HYPOOSMOTIC SWELLING TEST FOR SELECTION OF VIABLE SPERM FOR INTRACYTOPLASMIC SPERM INJECTION IN MEN WITH COMPLETE ASTHENOZOOSPERMIA, Fertility and sterility, 65(5), 1996, pp. 972-976
Objective: To determine the ability of the hypo-osmotic swelling test
to select viable sperm from nonmotile sperm samples for intracytoplasm
ic sperm injection (ICSI). Design: Nonrandomized, sequential comparati
ve study. Patients: Thirteen couples enrolled in our ICSI program had
16 cycles in which sperm preparations with 0% motility were obtained.
Five cycles used cryopreserved epididymal sperm with complete asthenoz
oospermia. Interventions: In eight cycles, the semen samples were wash
ed through a Percoll gradient and sperm mere selected randomly for ICS
I. In another eight cycles, the washed sperm were placed in a hypo-osm
otic solution (75 mM fructose; 25 mM sodium citrate dihydrate) and the
sperm with curled tails taken up with the microinjection needle, rins
ed, and used for ICSI. Main Outcome Measures: Fertilization rate per o
ocyte injected as determined by the presence of two pronuclei at 18 ho
urs after retrieval and embryo cleavage rate per oocyte injected at 48
hours after retrieval. Results: With random sperm injection, the fert
ilization and cleavage rates were 26% and 23%, respectively. In contra
st, after injection of sperm selected using the hypo-osmotic swelling
test, fertilization and cleavage rates were significantly greater (43%
and 39%, respectively). There were three pregnancies in the eight-cyc
les with the hypo-osmotic swelling test-selected sperm, including two
from frozen epididymal sperm. Conclusion: Based on these preliminary o
bservations, we believe that the hypo-osmotic swelling test will prove
to be valuable for increasing fertilization and cleavage rates and pr
egnancy rates in ICSI cycles where no motile sperm are recovered.