- 10.00: Trial lecture: The Role of antioxidants in male fertility with a focus on cryopreservation outcomes
- 12.00: Public defence
The ordinary opponents are:
- First opponent: Professor Jens Fedder, Odense University Hospital and University of Southern Denmark
- Second opponent: Associate Professor Amin Sayyari, The Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU)
- Leader of the committee: Professor Parisa Gazerani, OsloMet
The leader of the public defense is Professor Mari Charlotte Wik Myhrstad, OsloMet.
The main supervisor is Associate Professor Oliwia Witczak, OsloMet.
The co-supervisors are Professor Trine B. Haugen, OsloMet and PhD Mette Haug Stensen, Volvat Spiren, Norway.
Download the thesis from ODA (oda.oslomet.no).
Thesis abstract
Male fertility is often linked to poor semen quality. Oxidative stress, caused by excessive production of reactive oxygen species, can also impact male fertility, leading to sperm DNA damage at various stages of sperm development. Notably, reactive oxygen species production can also be caused by cryopreservation, a technique commonly used by in-vitro fertilization clinics to preserve and store semen samples for future use.
While polyunsaturated fatty acids, abundantly present in spermatozoa, significantly contribute to semen quality, the role of L-carnitine is also crucial. L-carnitine is involved not only in the metabolism of fatty acids but also in antioxidant defence.
This research primarily aimed to investigate the effect of naturally occurring seminal L-carnitine on human sperm parameters in both fresh and post-thawed semen samples. We also explored alternative methods for assessing sperm DNA damage, using bull sperm as a comparative model due to its biological similarity to human sperm cells.
Findings
We found that seminal L-carnitine levels positively correlated with palmitic acid, docosahexaenoic acid, and total omega-3 polyunsaturated fatty acids in spermatozoa. L-carnitine levels were not linked to body mass index, indicating that the reduced semen quality associated with obesity is unrelated to L-carnitine.
We also showed that both naturally occurring seminal L-carnitine and L-carnitine supplemented to the cryopreservation solution improved sperm motility and mitigated the oxidative stress caused by freezing.
Furthermore, we investigated alternative approaches for evaluating sperm DNA damage. The Sperm Chromatin Structure Assay (SCSA) test is the gold standard method for assessing sperm DNA damage, but it is costly and time consuming.
Our study found that SCSA and Sperm Chromatin Dispersion (SCD) tests effectively identified increased DNA damage in spermatozoa, whereas the Sensitive Recognition of Individual DNA Ends (STRIDE) test did not.
Conclusion
In conclusion, our research highlights the positive impact of L-carnitine in semen quality in both fresh and post-thaw semen samples, suggesting potential clinical applications.
Additionally, the development of cost-effective DNA damage tests like SCD test could provide more accessible diagnostic tools for the detection of DNA damage in spermatozoa.
