Evaluation of human sperm function after being cryopreserved within the zona pellucida.
OBJECTIVE
To investigate the fertilization ability, chromatin structure, and DNA integrity of spermatozoa after being cryopreserved within an empty zona pellucida (ZP).


METHODS
Prospective study.


METHODS
Reproductive research center in a university-affiliated hospital.


METHODS
Normozoospermic patients.


METHODS
Spermatozoa were cryopreserved within the ZP or with traditional methods.


METHODS
The sperm recovery rate, sperm motility, fertilization ability, chromatin structure, and DNA integrity were assessed before and after cryopreservation.


RESULTS
Significantly higher sperm recovery rate was identified for the spermatozoa cryopreserved within the ZP than those cryopreserved with traditional methods, but the motility recovery was similar. Frozen-thawed samples showed increased damage to the sperm chromatin and DNA, which were assessed by acridine orange test (AO) and terminal deoxynucleotidyl transferase-mediated dUDP nick-end labeling assay; however, no difference of chromatin and DNA integrity was observed for spermatozoa cryopreserved within the ZP or with traditional methods. In addition, the fertilization ability, as assessed by injecting spermatozoa into hamster oocytes, was similar for spermatozoa cryopreserved with different cryopreservation methods.


CONCLUSIONS
Cryopreservation of spermatozoa within an empty ZP results in higher sperm recovery rate, and the post-thaw sperm functions of spermatozoa cryopreserved within the ZP are comparable with spermatozoa cryopreserved with traditional methods.
Ye
Yinghui
Y
Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
Xu
Chenming
C
Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
Qian
Yuli
Y
Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
Jin
Fan
F
Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
Huang
Hefeng
H
Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China. Electronic address: huanghefg@hotmail.com.
D000818:Animals; D002843:Chromatin / Q000648:ultrastructure; D006224:Cricetinae; D015925:Cryopreservation; D004247:DNA / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D011446:Prospective Studies; D013075:Sperm Capacitation / Q000502:physiology*; D020554:Sperm Injections, Intracytoplasmic; D013081:Sperm Motility / Q000502:physiology; D013094:Spermatozoa / Q000502:physiology*; D015044:Zona Pellucida / Q000502:physiology*
D002843:Chromatin; D004247:DNA