(A) The effects of stronger and/or longer photobleaching on preimplantation development were investigated. Preimplantation development of the embryos subjected to 3-fold stronger (300 μW) and/or 6-fold longer (30 s) bleaching than the standard conditions (110 μW; 5 s). Confocal images of embryos during FRAP analysis. ROIs are indicated by red rectangles. Scale bar = 10 μm. The blastocysts shown on the right were derived from the FRAP-analyzed zygotes shown on the left. (Scale bar = 100 μm). (B) Rate of development of embryos subjected to standard (110 μW, 5 s) and stronger and longer (300 μW, 30 s) bleaching: unbleached control, white; standard, gray; and stronger/longer bleaching, black. Three independent experiments were performed in which at least 42 embryos were examined in total. Two-cell, 4–8 cell, morula (Mor), and blastocyst (Blast) stages were observed at 24, 48, 72, and 96 hpi, respectively. There is no significant difference between 110 μW, 5 s and 300 μW, 30 s; P value by Fisher’s exact test is P < 0.9999 (2C-Mor.) and P = 0.7136 (Blast.).