Human sperm chromosomal aberrations induced by whole-body γ-ray radiation

Chromosomal complements of 138 spermatozoa from two individuals exposed to whole-body 60Co irradiation six and seven years ago and 240 spermatozoa from six healthy men were analyzed. All the chromosomal complements were obtained by interspecific fertilization between human spermatozoa and zona-free hamster oocytes in vitro. The results were as follows: (1) Late genetic effect of radiation in human spermatozoa indicated that the target cells were spermatogonia. (2) A higher frequency of chromosome abnormalities was detected in spermatozoa stemming from injured spermatogonia. Most of the structural abnormalities of chromosome observed in this study were acentric fragment, break, translocation, dicentric, quadriradial, ring chromosome and deletion. (3) The chromosomal abnormalities caused no observable difference in sperm fertilization ability. (4) The proportion of Y-sperm to X-sperm was 1.6:1, which was significantly higher than that in control