Fe(III) Is Essential for Porcine Embryonic Development via Mitochondrial Function Maintenance

Iron is an important trace element involved in several biological processes. The role of iron in porcine early embryonic development remains unknown. In the present study, we depleted iron (III, Fe3+) with deferoxamine (DFM), a specific Fe3+ chelator, in cultured porcine parthenotes and monitored embryonic development, apoptosis, mitochondrial membrane potential, and ATP production. Results showed biphasic function of Fe3+ in porcine embryo development. 0.5 mu M DFM obviously increased blastocyst formation (57.49 +/- 2.18% vs. control, 43.99 +/- 1.72%, P < 0.05) via reduced (P < 0.05) production of reactive oxygen species (ROS), further increased mitochondrial membrane potential and ATP production in blastocysts (P < 0.05). 0.5 mu M DFM decreased mRNA expression of Caspase 3 (Casp3) and increased Bcl-xL. However, results showed a significant reduction in blastocyst formation in the presence of 5.0 mu M DFM compared with the control group (DFM, 21.62 +/- 3.92% vs. control, 43.99 +/- 1.73%, P < 0.05). Fe3+ depletion reduced the total (DFM, 21.10 +/- 8.78 vs. control, 44.09 +/- 13.65, P < 0.05) and increased apoptotic cell number (DFM, 11.10 +/- 5.24 vs. control, 2.64 +/- 1.43, P < 0.05) in the blastocyst. An obvious reduction in mitochondrial membrane potential and ATP level after 5.0 mu M DFM treatment was observed. Co-localization between mitochondria and cytochrome c was reduced after high concentration of DFM treatment. In conclusion, Fe3+ is essential for porcine embryonic development via mitochondrial function maintenance, but redundant Fe3+ impairs the function of mitochondria.