Effect of epigallocatechin-3-gallate (EGCG) on embryos inseminated with oxidative stress-induced DNA damage sperm

ABSTRACT

Cryopreservation can induce damage in human spermatozoa through reactive oxygen species (ROS) generation. To reduce the potential risk of oxidative stress-induced sperm DNA damage, addition of different epigallocatechin-3-gallate (EGCG) concentrations were performed to determine the optimum concentration which was beneficial for IVF outcome for both fresh and frozen-thawed sperm. Next, the mouse sperm model exhibiting oxidative stress-induced DNA damage by exogenously treating with H₂O₂ but overcoming the low fertilization rate of frozen-thawed sperm was used to investigate the effect of EGCG on the embryonic development and the potential EGCG-mediated effects on ataxia telangiectasia mutated (ATM) pSer-1981 in zygotes, the latter was known for leading to the activation of major kinases involved in the DNA repair pathway and the cell cycle checkpoint pathway. We found the fertilization and embryonic development of embryos inseminated with frozen-thawed sperm was impaired compared to fresh sperm. EGCG promoted the development of embryos inseminated with both types of sperm at optimum concentration. In embryos inseminated with the H₂O₂ sperm, fertilization, embryonic development, and the time at which the cleavage rate of one-cell embryos reached ≥95% were not affected by EGCG treatment. However, the EGCG-treated group required less time to achieve 50% cleavage rate of one-cell embryos, and the EGCG-treated zygotes showed enhanced expression of ATM (pSer-1981) than the untreated group. EGCG at optimum concentrations may exert beneficial effects by modulating the ATM activation and moving up the time to enter into mitotic (M) phase.

Abbreviations

ROS: reactive oxygen species; EGCG: epigallocatechin-3-gallate; ATM: ataxia telangiectasia mutated; M: mitotic

KEYWORDS:

• Sperm cryodamage
• DNA repair
• EGCG
• ATM
• cell cycle

Acknowledgments

We are grateful for the support from Center for Neuroscience, Shantou University Medical College for the utilization of the laser confocal microscopy.

Disclosure statement

No potential conflict of interest was reported by the authors.

Author contributions

Designed the study, analyzed data, revised the paper, and approved the final version: ZL; performed the research, analyzed data, drafted the article, and approved the final version: MC, WL, WX.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (Project No. 30872771, 81070542 and 81471522) and the Natural Science Foundation of Guangdong Province of China (Project No. 81515031102000010, 10151503102000020 and 20160203).