Abstract
Airport security systems commonly employ X-ray scanners for baggage screening, creating the possibility of unintended radiation exposure to biological materials, such as transported semen used in assisted reproductive technologies (ART). This review summarizes the current knowledge on X-ray-induced oxidative stress and evaluates its potential impact on semen quality across animal species. Semen is highly vulnerable to oxidative damage due to the abundance of polyunsaturated fatty acids in spermatozoa membranes and the limited cytoplasmic antioxidant reserves within the cells. Although seminal plasma contains substantial enzymatic and non-enzymatic antioxidants, excessive reactive oxygen species (ROS) generated by X-ray exposure can overwhelm endogenous defenses, leading to DNA fragmentation, lipid peroxidation, mitochondrial dysfunction, and impaired motility. Four key studies investigating the impact of airport-related X-ray exposure on semen quality in dogs, bulls, cats, and stallions demonstrated variable outcomes. Reported effects ranged from reduced motility and membrane function to increased double-stranded DNA damage and decreased embryo development, although one study in stallions found no detrimental effects at doses typically used in airport screening. These inconsistencies highlight species-specific sensitivity, differences in semen storage conditions, and exposure dose variations. Overall, evidence indicates that airport X-ray screening may pose a risk to spermatozoa structural and functional integrity. Future strategies, including the incorporation of antioxidants or radioprotective agents into semen extenders, optimization of packaging systems, and real-world exposure assessments, are needed to safeguard the quality of shipped semen during air transport.

Key words: Radiation; ROS, Semen quality; Spermatozoa, X-ray.