| Research Abstract |
The chromosome constitution of human spermatozoa was studied using our interspecific in vitro fertilization system between human sperm and zona- free hamster oocytes. The results are as follows:
1.Effects of gamma-rays: Total numbers of 6,977 and 6,932 sperm were analyzed in the control and irradiated groups. Within a dose range from 6.4 to 109.3 cGy, the incidence of sperm with gamma-ray-induced structural chromosome aberrations increased linearly with increasing dosage. The incidence of breakage-type aderations was far higher than that of exchange- type aberrations. The dose-dependent increase was linear in the former, whereas it was quadratic in the latter.
2.Effects of antineoplastic agents: Total numbers of 728 and 650 sperm were analyzed in the control and chemical-treated groups. The incidence of sperm with structural chromosome aberrations were 24.3%,47.3%,54.1% and 50.7% in bleomycin (50 ug/ml, 90 min), daunomycin (1 ug/m, 90 min),methyl methanesulfonate (100 ug/ml, 120 min), tr
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iethylenemelamine (0.1 ug/ml, 120 min) groups respectively, showing significantly higher incidences than those in matched controls. No significant in crease was found in cyclophosphamide 1-1000 ug/ml, 120 min) and mitomycin C (0.1-100 ug/ml, 120 min) groups.
3.Spontaneous incidence of chromosome aberrations in human sperm: A total of 4,579 sperm from 22 men were analyzed. The mean incidences of aneuploidy and structural anomaly were 1.3/ and 15.1%. The latter incidence varied considerably from donor to donor (7.0-24.8%).
4.Chromosome analysis in frozen-thawed human sperm: Five different cryopreservation media were tested. Post-thaw motility of sperm was higher in KS-II medium and TEST-yolk buffer medium (50-70%) than in HSP medium, modified HSP medium and Ackerman's medium (10-40%). There was a great individual variation in survival rate of post-thaw sperm. Rates of post- thaw sperm penetration into hamster ova and subsequent sperm chromosome analysis were considerably low even in the former two media. Further improvement is necessary. Less
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