1. Center for Reproductive Medicine, Department of Obstetrics and Gynecology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Rd., Nanjing 210008, China
2. Central Research Lab, The Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Rd., Nanjing 210008, China
3. MRC Center for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
4. Orthopedic Hospital Research Center and Broad Stem Cell Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
5. Clinical Center for Stem Cells, The Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Rd., Nanjing 210008, China