INTRACYTOPLASMIC INJECTION OF HUMAN SPERM INTO THE HAMSTER OOCYTE (HAMSTER ICSI ASSAY) AS A TEST FOR FERTILIZING-CAPACITY OF THE SEVERE MALE-FACTOR SPERM

Objective: Our objective was to investigate the fertilizing ability of human sperm from severe male-factor patients, by microinjection of si ngle sperm into the hamster oocyte. Design: Semen samples of severe ma le factor either with a 0% penetration rate in the zona-free hamster t est or with a very low number of motile motile sperm for which perform ing the standard penetration test was impossible were used. For the co ntrol study, oligozoospermic semen samples with at least 10% penetrati on rare in zona free hamster rest were used. Setting: All materials we re collected from the National University Hospital, Singapore. Methods : There were 10 patients in both the experimental and the control grou ps. Intracytoplasmic sperm injection (ICSI) was carried out, The main outcome measures were sperm head decondensation and pronuclear formati on. Results: Twenty-one percent of the injected sperm could decondense and undergo male pronuclear formation. This rate was not significantl y different from that in the control study group (28%; P = 0.13). A sm all proportion of the oocytes was damaged during the procedure (9.2 an d 8.75% in experimental and control groups, respectively). Conclusions : Hamster-ICSI assay may be of benefit in predicting the sperm's abili ty for further development before allowing the patient to undergo the clinical program.