Researchers have found addition of L-proline to sperm freezing media can improve post thaw sperm parameters.
The data presented at ESHRE 2022, showed that sperm frozen in media with L-proline added at a concentration of 4 mmol/L (the highest concentration used in the study), had significantly higher vitality and progressive motility post thaw compared to the control. The production of reactive oxygen species was also significantly diminished when sperm was frozen in the 4 mmol/L L-proline enriched media. Sperm DNA fragmentation was also reduced, though not significantly.
L-proline has previously been shown to protect against freezing and thawing related sperm damage in equine animals and is a natural osmoprotectant. This study suggests a potential application for L-proline in human sperm cryopreservation, although further studies analysing clinical outcomes are required.
References: Moradi B, Faramarzi A, Ghasemi-Esmailabad S, Aghaz F, Hashemian AH, Khazaei M. L-proline as a novel additive to cryopreservation media improved post-thaw quality of human spermatozoon via reducing oxidative stress. Andrologia. 2022 Feb;54(1):e14301. doi: 10.1111/and.14301. Epub 2021 Nov 8. PMID: 34748671.