1. Department of Reproductive Medical Center, The Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541001, P.R. China
2. Department of Histology and Embryology, School of Basic Medical Sciences, Zunyi Medical University, Zunyi, Guizhou 563006, P.R. China
3. State Key Laboratory for Conversation and Utilization of Subtropical Agro‑Bioresources, Guangxi University, Nanning, Guangxi 530004, P.R. China