Oxidative Stress Measurement in Frozen/Thawed Human Sperm: The Protective Role of an In Vitro Treatment with Myo-Inositol

Despite its widespread use, sperm cryopreservation induces serious detrimental alterations in sperm function; indeed, it is commonly associated with decreased sperm viability and motility, and DNA fragmentation. Mechanisms of human sperm cryodamage are thought to be multifactorial, but oxidative stress seems to have a prominent role. A huge amount of data supported the cryoprotective effect of different antioxidants able to minimize the detrimental effects of reactive oxygen species (ROS) and improve the quality of spermatozoa. Among others, myo-inositol is one of the most powerful and has been reported to be effective in improving sperm quality and motility when used both in vivo and in vitro. This study aimed to determine the in vitro impact of myo-inositol in ameliorating sperm oxidative status during sperm cryopreservation. In particular, we demonstrated a significant improvement of sperm parameters (vitality and motility) when myo-inositol was added after sperm thawing (p < 0.05). Moreover, we showed that myo-inositol induces a significant increase in oxygen consumption, the main index of oxidative phosphorylation efficiency and ATP production. Finally, by means of 2D-electrophoresis, we demonstrated a significant decrease in the level of carbonyl groups, the main structural changes occurring in conditions of oxidative stress (p < 0.05). In conclusion, the sperm cryopreservation procedure we developed, assuring the reduction of ROSinduced sperm modifications, may improve the in vitro procedure currently used in ART laboratory for sperm cryostorage.

Automated summary

Despite the widespread use of sperm cryopreservation, it can cause detrimental alterations in sperm function, including decreased viability, motility, and DNA fragmentation. Oxidative stress appears to play a prominent role in the mechanisms of human sperm cryodamage. Antioxidants such as myo-inositol have been shown to minimize the detrimental effects of reactive oxygen species (ROS) and improve sperm quality and motility. This study demonstrated that post-thaw addition of myo-inositol significantly improved sperm parameters, increased oxygen consumption, and decreased carbonyl groups, indicating reduced oxidative stress. These findings suggest that the developed sperm cryopreservation procedure may improve current in vitro techniques used for sperm cryostorage in assisted reproductive technology (ART) laboratories.