PENETRATION OF CONCANAVALIN-A-TREATED CHINESE-HAMSTER OOCYTES BY GOLDEN-HAMSTER SPERMATOZOA IN-VITRO, AND CHROMOSOME ANALYSIS OF HYBRID 1-CELL ZYGOTES

Pretreatment of zona-free Chinese hamster (CH) oocytes with three kind s of lectin - concanavalin A (Con-A), phytohaemagglutinin-P (PHA) and wheat germ agglutinin (WGA) - was attempted in order to improve penetr ation by golden hamster (GH) spermatozoa in vitro. Con-A had no signif icant effect on penetration at 2 mu g/ml, adequately facilitated oocyt e-sperm fusion at 4 mu g/ml, and caused excessive sperm:binding and re sultant severe polyspermy at 10 mu g/ml. Neither PHA nor WGA had posit ive effects on sperm penetration at any concentrations (2-10 mu g/ml) examined. Using the Con-A (4 mu g/ml) pretreatment, high rates of inte rspecific fertilisation and subsequent chromosome analysis of hybrid 1 -cell zygotes were achieved, Among 258 CH oocytes used, 212 (82.2%) we re fertilised and 153 (72.2% of fertilised ova) developed to the first cleavage metaphase. Eventually, 132 CH-derived chromosome complements and 153 GH-derived ones were successfully karyoanalysed. Incidences o f aneuploidy and structural anomaly were 3.1% and 2.3% in CH complemen ts, and 1.4% and 6.5% in GH complements, respectively. These incidence s were not significantly different from those obtained by intraspecifi c in vivo fertilisation, suggesting that our interspecific in vitro fe rtilisation system does not cause chromosome aberrations.