1. Ningxia Medical University General Hospital, Yinchuan, Ningxia Hui Autonomous Region 750004, China
2. Ningxia Medical University School of Clinical Medicine, Yinchuan, Ningxia Hui Autonomous Region 750004, China
3. Key Laboratory of Fertility Maintenance, Ministry of Education, Yinchuan, Ningxia Hui Autonomous Region 750004, China
4. School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750004, China.