Effects of various concentrations of PUGNAc on preimplantation development of pig parthenogenetically activated diploids. Diploids were cultured in PZM3 with 0 (C, control; D, DMSO as vehicle control), 75, 150 and 300 µM PUGNAc. Trials were repeated at least three times in each experimental group, and the total numbers of cultured diploids for the analysis were 37, 38, 31, 31 and 39 for the control, vehicle control and 75, 150 and 300 µM PUGNAc groups, respectively. (A) Proportions of diploids at normally developing stages at each observation period. The different small letters (a, b) indicate significant differences in the proportions of diploids that developed to the most advanced stage at each observation period among the experimental groups (P < 0.05). The different capital letters (A, B) indicate significant differences in proportions of normally developing diploids at each observation period among the experimental groups (P < 0.05). (B) Typical images of
diploids cultured in the vehicle control group and 300 µM PUGNAc group from 4 to 144 h after electrostimulation. Seven out of ten (70%) diploids developed further than the expanded blastocyst stage in the vehicle control, and all 10 diploids cultured with 300 µM PUGNAc cased development at the 4-cell stage. Scale bar = 200 µm.