Peroxiredoxin 5 is essential for in vitro development of bovine SCNT embryos

Peroxiredoxin 5 (PRDX5) is an important peroxiredoxin with antioxidant and antiapoptotic functions. The objective of this study was to determine whether the antioxidant and antiapoptotic activities of PRDX5 play an essential role in the in vitro development of bovine SCNT embryos. We analyzed the expression patterns of PRDX5, and found the expression of PRDX5 in second meiotic metaphase oocytes, which persisted until the blastocyst stage IVF and SCNT embryos. In addition, PRDX5 transcript levels were significantly higher in SCNT embryos than those in IVF embryos. After PRDX5 inhibition, more embryos were arrested before eight-cell stage (53.0% vs. 35.4%, P < 0.05) and decreases were observed in the blastocyst rate (15.7% vs. 32.3%, P < 0.05), inner cell mass rate (24.45 ± 6.05% vs. 38.37 ± 6.83%, P < 0.05), and total cell number (90.8 ± 10.2 vs. 116.2 ± 10.8, P < 0.05). There were significant increases in reactive oxygen species levels at two-, four-, and eight-cell stages and the apoptosis rate of blastocysts (11.93 ± 2.12% vs. 4.25 ± 0.88%, P < 0.05). The expression levels of p53 and HSP70 were increased significantly, whereas the expression level of Bcl-2 was decreased significantly. These results suggest that the antioxidant and antiapoptotic activities of PRDX5 play important roles in the in vitro development of bovine SCNT embryos.