title: Fertilization of human oocytes in capillary tubes with very small numbers of spermatozoa.
abstract: Human oocytes can be fertilized with high rates of success under in-vitro conditions even if only low numbers of spermatozoa are used. A culture system has been developed in which fertilization is performed in haematocrit capillary tubes (length 75 mm; i.d. 0.8-0.9 mm). Oocytes were fertilized in 5-10 microliters of different sperm suspensions containing a total of 500, 1000, 2000 and 4000 spermatozoa per oocyte (0.1-0.4 x 10(6) spermatozoa/ml). Oocytes were obtained from 10 patients participating in an in-vitro fertilization programme; of these, 32 oocytes were fertilized in capillary tubes and 32 oocytes were cultured using standard methods (1 ml culture medium in tissue culture tubes; 0.1-0.2 x 10(6) spermatozoa/ml). The overall fertilization rate of oocytes cultured in tissue culture tubes was 78% (25/32) and the fertilization rates in capillary tubes using 4000, 2000, 1000 or 500 spermatozoa per oocyte were 71% (5/7), 86% (6/7), 60% (6/10) and 50% (4/8), respectively. The fertilization rate of mature oocytes was higher compared with immature oocytes when fertilization was performed in culture tubes (83 and 63%) or in capillary tubes (74 and 44%). Fertilization in capillary tubes using a 10 microliter of oocyte and spermatozoa suspension compared to 5 microliters seemed to provide better culture conditions, resulting in higher fertilization and cleavage rates. These preliminary results indicate that fertilization of human oocytes under in-vitro conditions can be achieved even with very low numbers of spermatozoa.
authors.affiliation: University of Bonn, Department of Obstetrics and Gynaecology, FRG.
authors.forename: H H
authors.initials: HH
authors.lastname: van der Ven
authors.forename: K
authors.initials: K
authors.lastname: Hoebbel
authors.forename: S
authors.initials: S
authors.lastname: al-Hasani
authors.forename: K
authors.initials: K
authors.lastname: Diedrich
authors.forename: D
authors.initials: D
authors.lastname: Krebs
mesh_terms: D005260:Female; D005307:Fertilization in Vitro / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008297:Male; D009865:Oocytes; D013076:Sperm Count; D013084:Sperm-Ovum Interactions