Figure 4

Assessment of cleavage, blastocyst, 2–4 cell embryo arrest and spontaneous embryo cleavage rates following microinjection with p66Shc hairpin RNAi molecules. Cleavage rate (A) and spontaneous cleavage rate (D) were evaluated at day-2 post insemination, while blastocyst rate (B) and arrest rate (C) were evaluated at day 8–9 post insemination. Although cleavage and blastocyst frequencies were significantly decreased (P < 0.001) in the embryos microinjected with the vehicle alone, an even greater significant decrease (P < 0.001) was observed in the p66Shc shRNAi microinjected oocytes (A, B). We observed a significant decrease (P < 0.05) in spontaneous oocyte cleavage rate following microinjection (D). A significant decrease in the frequency of arrested 2–4 cell embryos was achieved only following microinjection of short hairpin RNAi molecules against p66Shc (C). Bars with different letters represent significant differences between groups (P ≤ 0.05).