Successful Reprogramming Of Differentiated Cells By Somatic Cell Nuclear Transfer, Using In Vitro-Matured Oocytes With A Modified Activation Method

Therapeutic cloning has tremendous potential for cell therapy and tissue repair in some diseases. However, the efficiency of development of cloned human embryos by somatic cell nuclear transfer is still low. In the present study, the activation of cloned human embryos was investigated while using in vitro-matured oocytes. Pseudo-pronuclear formation and the subsequent development was compared with different activation parameters, including different durations of ionomycin and 6-dimethylaminopurine treatment. The results showed that somatic cells were successfully reprogrammed by modification of activation treatments while using in vitro-matured oocytes. The activation efficiency of cloned human embryos was significantly increased at durations of ionomycin at both 5 and 7min, despite different durations of 6-DMAP treatment. The results of blastocyst development showed that 20% of activated embryos developed to the blastocyst stage when the embryos were activated with 5 mu m ionomycin for 5min and 2mm 6-DMAP for 5h, which was significantly higher than those activated with other parameters. Moreover, we found that an increasing duration of 6-DMAP induced the formation of a single, large, pseudo-pronucleus in cloned human embryos and impaired subsequent development competence. In conclusion, successful reprogramming of human somatic cells was achieved using in vitro-matured oocytes by somatic cell nuclear transfer and improved with a modified activation method. Copyright (c) 2012 John Wiley & Sons, Ltd.