1. Department of Histology and Embryology, Jilin Medical University, Jilin, Jilin 132013, P.R. China
2. Medical Experimental Center, Jilin Medical University, Jilin, Jilin 132013, P.R. China
3. Reproductive Medicine Center of The Affiliated Hospital of Jining Medical College, Jining, Shandong 272029, P.R. China
4. Department of Urology, Affiliated Hospital of Jilin Medical University, Jilin, Jilin 132013, P.R. China