ABSTRACT
Oocytes at the dictyate stage from young (8-14 weeks) and old (12-15 months) BALB/c mice were manually isolated and UV-irradiated. They were cultured for 1 h in medium containing tritiated thymidine and chased for a further hour in cold thymidine medium before being incubated for 18-20 h in medium with no added thymidine. Oocytes which had developed to metaphase II were analysed following autoradiography. Pooled results from 14 replicate experiments revealed no significant age-related difference between the mean corrected grain count per cell [159.2 +/- 8.5 (86 cells) for young mice and 164.6 +/- 9.8 (70 cells) for the old animals]. Thus in the female mouse the oocyte's capacity to repair UV-induced damage is apparently maintained at a high level throughout reproductive life.
Subject(s)
DNA Repair/radiation effects , Maternal Age , Oocytes/radiation effects , Animals , Meiosis/radiation effects , Mice , Mice, Inbred BALB C , Ultraviolet RaysABSTRACT
Oocytes from fetal and neonatal mice were UV-irradiated, cultured in medium containing tritiated thymidine and analysed following autoradiography. As previously reported irradiated dictyate cells clearly displayed an increased grain count. However we detected no UV-induced response in oocytes at the leptotene, zygotene or pachytene stages of meiosis. This contrasts with the situation in spermatogenesis where high levels of repair can be induced in equivalent early prophase stages.
