Enhancing the post-thaw quality of Holstein bull semen using artichoke extract-loaded nanoliposomes in the extender

This study investigated the effects of artichoke extract-loaded nanoliposomes (ARE-NL) on the cryopreservation of bovine sperm. Semen from seven mature Holstein bulls was cryopreserved in a tris extender containing varying ARE-NL concentrations (0, 50, 100 and 200 μg/mL). The inclusion of 100 or 200 μg/mL of ARE-NL in the freezing media significantly enhanced sperm progressive motility, viability, membrane integrity and kinematic parameters. Additionally, these concentrations boosted antioxidant activity by increasing total antioxidant capacity, catalase and nitric oxide levels compared to the control group (p < 0.05). Furthermore, semen supplemented with 100 μg/mL of ARE-NL exhibited significantly lower concentrations of hydrogen peroxide and malondialdehyde, while enhancing enzymatic activity in seminal plasma compared to the control. The supplementation of 100–150 μg/mL of ARE-NL in the freezing media is expected to considerably decrease the transcription of apoptotic genes such as caspase 3 and Bax in sperm, while markedly inducing the expression of Bcl2 compared to the control (p < 0.05). Electron microscopy observations revealed that supplementation with 100 or 200 μg/mL of ARE-NL maintained the integrity of the acrosome and plasma membranes and preserved the ultrastructural integrity of cryopreserved bovine spermatozoa compared to the control group. In contrast, ARE-NL0 exhibited the most significant damage to the plasma and acrosome membranes. In conclusion, incorporating 100–150 μg/mL of ARE-NL into the Tris extender significantly reduced oxidative stress, improved redox balance, and enhanced the expression of apoptotic genes. Additionally, it helped preserve the ultra-structural integrity of the frozen-thawed semen characteristics of Holstein bulls.