Figure 7

NHEJ-mediated repair of ETP-induced DNA DSBs is not sufficient to rescue embryonic development. The developmental potential of oocytes challenged with an ETP insult was analysed whereby treated oocytes were provided a minimum recovery time of 4 h prior to in vitro fertilisation. (a) Embryonic competency was not appreciably altered within the 4 h post-ETP recovery window with limited numbers of embryos progressing beyond the two-cell stage of embryogenesis. (b) In addition, a notable reduction in fertilisability was evident in all oocytes derived of both the treated and untreated oocytes. (c) Analysis of metaphase plate integrity at 4 and 6 h recovery time points indicated that neither period of post-treatment recovery was sufficient to ameliorate the incidence of metaphase plate misalignment. Statistical significance was determined using ANOVA and Tukey–Kramer HSD. *p ≤ 0.05 and **p ≤ 0.01. Each experiment was conducted on a minimum of three biological replicates, with the total number of embryos assessed across these replicates being: vehicle = 40; untreated = 50; 100 µg/ml  ETP = 40; 200 µg/ml  ETP = 27. In regard to oocytes, each experiment was conducted on a minimum of three biological replicates, with each replicate comprising a minimum of 30 oocytes. All data are expressed as means ± S.E.M.