Open Veterinary Journal, (2026), Vol. 16(4): 1977-1986

Review Article

10.5455/OVJ.2026.v16.i4.2

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Impact of airport X-ray security screening on the quality of shipped animal semen: Oxidative stress, irradiation effects, and future perspectives

Anak Agung Gde Oka Dharmayudha^1,2, I Ketut Puja³, I Wayan Nico Fajar Gunawan², Wiwik Misaco Yuniarti⁴ and Bambang Sektiari Lukiswanto^4*

¹Doctoral Program Student, Faculty of Veterinary Medicine, Airlangga University, Surabaya, Indonesia

²Laboratory of Veterinary Clinical Diagnostic, Pathology and Radiology, Faculty of Veterinary Medicine, Udayana University, Denpasar, Indonesia

³Laboratory of Veterinary Genetic and Technology Reproduction, Faculty of Veterinary Medicine, Udayana University, Denpasar, Indonesia

⁴Department of Veterinary Clinic, Faculty of Veterinary Medicine, Airlangga University, Surabaya, Indonesia

*Corresponding Author: Bambang Sektiari Lukiswanto. Department of Veterinary Clinic, Faculty of Veterinary Medicine, Airlangga University, Surabaya, Indonesia. Email:bamsekti [at] yahoo.com

Submitted: 28/12/2025 Revised: 15/03/2026 Accepted: 26/03/2026 ;Published: 30/04/2026

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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 generated by X-ray exposure can overwhelm endogenous defenses, leading to deoxyribonucleic acid (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.

Keywords: Radiation, ROS, Semen quality, Spermatozoa, X-ray.

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Introduction

Over the past 50 years, significant advancements in livestock reproductive management have been achieved. This progress is increasingly dependent on scientific and research breakthroughs, coupled with a comprehensive understanding of the underlying physiological reproductive processes (Verma et al., 2012). Assisted reproductive technologies (ART) are now employed in animal breeding, providing a means to efficiently produce genetically superior offspring (Crowe et al., 2021; Niżański, 2022). Advancements in animal ART have significantly increased the use of biological materials, particularly semen, necessitating the transport of numerous samples across considerable geographical distances. The safe and reliable transport of these samples is critical to the success of ART procedures (Til et al., 2016). The successful dissemination of genetically superior livestock to other farms via ART following transportation is a key factor influencing reproductive outcomes (Lee et al., 2023).

Air transportation of biological materials, including sperm, has become increasingly common (Hendricks et al., 2010). Airport authorities in many countries implement security checkpoints to ensure passenger safety during both domestic and international air travel to prevent the transport of hazardous materials from being brought onboard (Gloor et al., 2006). Checkpoints use X-ray scanners to screen passengers and their luggage. X-rays are a component of the electromagnetic spectrum, a form of ionizing radiation (IR) with wavelengths ranging from 0.1 to 100 Å (Valipour et al., 2017). In this respect, semen samples and other sensitive genetic/biologic samples transported in checked or carry-on baggage may also be inadvertently exposed to X-ray radiation during airport security screening. The penetration capacity of X-rays used at security checkpoints allows their radiation energy to be absorbed by biological molecules, potentially causing harmful cellular effects. Exposure to X-ray radiation has been associated with risks of infertility (Kesari et al., 2018). In humans, X-ray exposure can cause a decrease in sperm quality, particularly motility, viability, and deoxyribonucleic acid (DNA) integrity (Shawrang et al., 2022) and has been linked to genetic fragmentation and DNA methylation (Wdowiak et al., 2019). In mice, X-ray irradiation induces morphological abnormalities and DNA damage (Saghaei et al., 2019), whereas in dogs, it damages the spermatozoa membrane (Sakalauskaitė et al., 2016). This review focuses on the impact of X-ray irradiation during airport security procedures on oxidative stress and its subsequent effects on the quality of animal semen.

Articles on oxidative damage, X-ray radiation exposure, semen quality, and the effects of X-ray exposure on semen quality in various animal species were reviewed. To identify relevant publications, literature searches were conducted using Google Scholar and PubMed. Keywords used included “oxidative stress,” “X-ray oxidative stress,” “X-ray irradiation,” “airport x-ray,” “oxidative stress and sperm quality,” “X-ray exposure and sperm quality,” “Airport X-ray on semen quality,” and “antioxidant semen diluent.”

All identified articles were screened and evaluated using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Eligible articles were compiled and categorized based on the following criteria: (1) general descriptions of oxidative stress, (2) oxidative stress induced by X-ray exposure, (3) impact of X-rays and oxidative stress on sperm/semen quality, (4) impact of X-ray airport security on sperm/semen quality in animals across species whenever references were available, and (5) incorporation of antioxidants in semen diluent. We excluded articles not related to reproductive biology, oxidative stress, or radiation exposure (Fig. 1). Because the number of studies specifically addressing X-ray exposure on semen in airport security is extremely limited, a narrative review approach was adopted rather than a systematic meta-analysis.

Fig. 1. Flowchart of the selection process of relevant articles/references used in this review using PRISMA.

General concept of oxidative stress

Oxidative stress was first introduced in 1985 and is defined as an imbalance between oxidants and antioxidants that disrupts redox signaling and regulation, ultimately leading to molecular damage (Sies, 2015; Sies, 2020; Abdelazim and Abomughaid, 2024; Muscolo et al., 2024). Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are major contributors to oxidative stress, arising from various intrinsic and extrinsic biological processes. In intrinsic processes, cellular ROS can be produced endogenously in mitochondria as the main intracellular site for oxidative phosphorylation and other organelles such as peroxisomes and endoplasmic reticulum (ER) via ER stress (Bhandary et al., 2013).

Additional endogenous sources of ROS include nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase, xanthine oxidase, and endothelial nitric oxide synthase (Aranda-Rivera et al., 2022). However, ROS are generated as by-products of normal cellular metabolism, especially in the mitochondria. Extrinsic sources, such as exposure to radiation and xenobiotic compounds, can increase ROS production (Fig. 2) (Forman and Zhang, 2021). Oxidative stress occurs when excessive accumulation of intracellular ROS occurs (Fig. 3) (Reddy, 2023).

Fig. 2. Schematic figure of oxidative stress caused by intrinsic and extrinsic biological processes.

Fig. 3. X-ray exposure induces oxidative stress by directly damaging DNA and organelles and indirectly generating ROS through water radiolysis, mitochondrial activity, and enzyme activation, leading to lipid peroxidation and reduced antioxidant defenses.

A weakened endogenous antioxidant defense system can also contribute to oxidative stress (Dutta et al., 2019; Mannucci et al., 2022). Excessive ROS levels lead to various disorders (Chaudhary et al., 2023) and damage essential macromolecules, including nucleic acids, proteins, and lipids (Martemucci et al., 2022; Liu et al., 2023). Cell death via apoptosis, autophagy, lipid peroxidation, and DNA damage occurs (Hong et al., 2024).

Impact of oxidative stress on sperm quality

Semen naturally contains abundant antioxidants. These antioxidants are present in both spermatozoa and seminal plasma, but are mostly concentrated in the seminal plasma (Shiva et al., 2011). Seminal plasma includes enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and glutathione peroxidase (GPx), as well as non-enzymatic antioxidants such as vitamin C and E (Bansal et al., 2010). However, when ROS levels exceed the antioxidant capacity of semen, oxidative stress occurs. Oxidative stress is reported to damage sperm DNA integrity, potentially impacting embryo developmental capacity and offspring health and well-being (Aitken, 2020). Elevated ROS levels negatively impact sperm viability, motility, and morphology (Li et al., 2023). Furthermore, excessive ROS can impair sperm function via DNA damage, lipid peroxidation, compromised membrane integrity, increased permeability, enzyme inactivation, and apoptosis (Takeshima et al., 2021; Kowalczyk, 2022; Takalani et al., 2023). Spermatozoa membranes exhibit a high concentration of polyunsaturated fatty acids, rendering them particularly susceptible to elevated ROS levels. Elevated ROS levels promote lipid peroxidation in spermatozoa membranes, reducing membrane flexibility and motility. Oxidative stress also compromises spermatozoa axonemal and mitochondrial function and impairs DNA integrity, RNA, and protein synthesis (Pourmasumi et al., 2020).

X-ray irradiation induces oxidative stress

X-rays have been a mainstay of medical practice for several decades. Its ability to penetrate various materials, including the human body, allows for the visualization of internal anatomy via techniques such as radiography and computed tomography CT scans, effectively creating silhouettes of internal organs and structures (Yamashita et al., 2020). This technology has revolutionized the diagnosis and treatment of numerous diseases by providing non-invasive access to previously inaccessible internal tissues, facilitating early detection and intervention (Wang and Zhang, 2019). X-ray exposure is an important source of exogenous ROS and a major pathway for endogenous ROS production in the body (Dong et al., 2020). The impact of X-ray irradiation depends on the exposure dose (Saghaei et al., 2019). However, small doses can trigger oxidative stress (Puthran et al., 2009).

Exposure to X-rays causes oxidation events that change atomic structures through direct interactions of radiation with target macromolecules and indirect interactions (i.e., the formation of ROS through water radiolysis products), causing damage to DNA and subcellular organelles (Valipour et al., 2017). Damage is directly caused by IR from X-rays. The IR can ionize DNA atoms, causing the formation of lesions in the DNA, such as single-stranded DNA breaks (SSB), double-stranded DNA breaks (DSB), and DNA-protein cross-links (Risom et al., 2003; Valipour et al., 2017). Indirectly, X-rays can hydrolyze water molecules, generating free radicals such as hydroxyl radicals (OH•), hydrogen peroxide (H₂O₂), and superoxide anions (O₂•–). These ROS are highly reactive and can damage various cellular components (Liu et al., 2008; Sotomayor et al., 2024). Moreover, X-rays enhance mitochondrial electron transport activity and increase mitochondrial content, resulting in elevated ROS production, particularly during cell cycle arrest at the G2/M phase (Yamamori et al., 2012). Moreover, X-ray exposure has been reported to activate enzymes such as NADPH oxidase, lipoxygenase, and nitric oxide synthase, which further amplify the production of ROS and RNS (Wei et al., 2019). X-ray irradiation has also been reported to increase lipid peroxidation, as indicated by elevated levels of malondialdehyde (MDA), and reduce antioxidant levels. This reduction weakens the cell’s defense against oxidative stress, making cells more prone to damage (Gündüz et al., 2021; Yilmaz et al., 2023).

Effect of X-ray irradiation on sperm quality

In experimental studies, exposure to X-ray irradiation negatively affects sperm quality. X-ray exposure consistently reduces sperm count and motility in mice, rats, and rabbits, with higher doses causing severe effects (Klepko et al., 2013; Saghaei et al., 2019; Hariyoto et al., 2020). Increasing the dose, especially when the exposure is repeated, has been reported to raise the proportion of sperm with abnormal morphology and to induce observable DNA damage (Klepko et al., 2013; Saghaei et al., 2019; Hariyoto et al., 2020). Direct sperm exposure to radiation has also been reported to reduce fertilization rates and impair embryonic development (Searle and Beechey, 1974; Vazirov et al., 2024). As mentioned earlier, the damage induced by X-ray irradiation is dose-dependent. Doses of 20–100 mGy have been reported to increase MDA levels and decrease antioxidant levels such as GSH, SOD, and CAT (Zosangzuali et al., 2020; Teng et al., 2025). Significant oxidative DNA damage occurs at doses of 0.3–0.5 Gy (Sakamoto et al., 2024). Severe oxidative stress, indicated by elevated ROS, DNA damage, and altered antioxidant enzyme activity, is observed at doses of 4–8 Gy (Risom et al., 2003; Zamyatina et al., 2024; Romodin, 2025; Teng et al., 2025).

Effect of X-ray exposure at airport security on the quality of shipped semen

In addition to their use in diagnostics and radiotherapy, X-rays are employed in security scanners as part of a multilayered system designed to prevent dangerous items from being carried by passengers or loaded onto aircraft (Fig. 4). The risk of terrorism and other security threats has prompted stricter airport screening procedures (Gloor et al., 2006). X-ray exposure from airport security systems ranges from 0.5 to 1 micro-Sievert (μSv) (England and Keane, 1995). Cargo may also be exposed to X-ray irradiation during the airport’s entry and exit processes. The effects of X-ray exposure from airport security systems on the semen quality of various animal species have been reported in several studies (Table 1).

Table 1. Airport X-ray exposure and its effects on sperm quality across species.

Fig. 4. Carry-on baggage X-ray scanners are commonly used as security measures in airports (Point Security Inc., 2022).

Three studies investigated the impact of airport security X-rays on sperm quality in canine, feline, and bovine species, while one study in horses was an experimental study using an X-ray device with exposure levels adjusted to mimic those of a typical airport. A study by Sakalauskaitė et al. (2016) examined chilled semen from 10 healthy dogs with normal sperm concentration exposed to airport security X-ray irradiation (HI-SCAN 100100 T). A single exposure resulted in a decrease in total and progressive motility and a reduction in functional membrane integrity over 5 days of storage.

Another study used frozen semen samples from 9 bulls stored in a dry shipper at −160°C with multiple exposures (0–3 times) to X-rays that followed airport protocols for carry-on and checked luggage and reported that chromatin integrity was maintained and unaffected, although three exposures reduced oocyte cleavage rates and blastocyst development (Hendricks et al., 2010). The field study provided the most comprehensive analysis, evaluating frozen semen from domestic and fishing cats exposed to radiation measured by dosimetry at an estimated dose of 16 mrem per screening, and showed that all radiation levels affected sperm motility, while three screening sessions caused significantly more DSB damage than a single exposure or the control (Gloor et al., 2006). England and Keane (1995) found that exposure of stallion semen to X-ray irradiation at doses of 0.5–1.0 μSv, the levels commonly used for airport screening, had no observable impact on motility, morphology, viability, or fertility, as demonstrated by high pregnancy success rates with healthy foals born in all treatment groups. All studies used different methodological approaches, and not all assessed fertility rates after radiation exposure. Collectively, these studies demonstrate that X-ray screening at airports presents a potential risk to transported biological samples, with reported effects ranging from reduced motility and membrane function to DNA damage and impaired fertilization capacity.

Although several studies have investigated the effects of IR on spermatozoa, only a few studies have specifically examined the impact of airport security X-ray screening on transported semen samples. Currently, only four studies have directly addressed this issue across different animal species. This limited evidence base highlights the need for cautious interpretation and further research under real transport conditions. The variability in reported outcomes may also be influenced by differences in biological and methodological methods among studies. Species-specific variations in sperm physiology, differences in semen preservation methods (chilled vs. cryopreserved), and variation in the antioxidant capacity of seminal plasma may contribute to different levels of radiation-induced oxidative stress susceptibility.

The radiation doses used in many experimental studies investigating sperm damage typically range from mGy to Gy. In contrast, the radiation emitted by airport security scanners is extremely low, generally estimated at 0.5–1 μSv per scan. Therefore, the extrapolation of findings from high-dose experimental studies to real-world airport exposure should be interpreted cautiously.

Future perspectives

Air transport of semen from animals with globally superior genetics is possible, but X-ray screening of all baggage at airports is challenging due to radiation exposure, which may impact semen quality. The general review in this article has explained the negative impact of oxidative stress on sperm quality. Exposure to X-ray irradiation can trigger oxidative stress, which can impact sperm quality. Several field studies have shown varying results. Some studies reported significant effects, whereas others reported no significant impact. Nevertheless, the radiosensitive nature of sperm suggests the need for radiation protection for semen samples that may be exposed to X-rays during airport screening.

In the future, exploring practical strategies that can minimize radiation-induced oxidative damage during semen transport will be important. One solution is to develop antioxidant-containing semen solvents to protect spermatozoa from the negative impacts of X-ray irradiation. Although semen contains many natural antioxidants (in both spermatozoa and seminal fluid), X-ray exposure can reduce the levels of these endogenous antioxidants, causing an imbalance between ROS and antioxidants, causing oxidative stress. The use of antioxidants can neutralize excess ROS production, thereby preventing oxidative damage. The use of antioxidants as additives in semen extenders is well established. Several studies have reported their effectiveness in maintaining sperm quality, motility, viability, and membrane integrity during the cooling or freezing process. Incorporating antioxidants into semen extenders can enhance the antioxidant activity of SOD, CAT, and GPx (Allai et al., 2023; Sigit et al., 2024; Sohail et al., 2024; Loetjettanarom et al., 2025; Vakili et al., 2025). These studies generally employ antioxidants as additives or supplements to semen extenders for storage. Further research on their use as additives in semen intended for air transport is needed to better understand the protective effects of antioxidants against X-ray radiation exposure during airport security screening. Additional approaches, such as improving packaging systems, evaluating the use of radioprotective additives, and conducting controlled field trials on X-ray exposure during real transport scenarios, may also contribute to the maintenance of semen quality during air shipment.

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Conclusion

Airport X-ray security screening can compromise the quality of transported semen through oxidative stress-mediated mechanisms. Exposure to X-ray irradiation can reduce endogenous antioxidant levels and increase ROS generation, leading to lipid peroxidation, DNA damage, and impaired sperm motility and function, although seminal plasma contains its own antioxidant defenses. Studies across species demonstrate inconsistent outcomes, with some showing significant reductions in semen quality and others reporting no detectable effects at typical airport exposure doses. These variations likely reflect differences in species sensitivity, semen preparation techniques, freezing or chilling conditions, and radiation dose intensity. Nonetheless, the radiosensitive nature of spermatozoa underscores the importance of implementing protective strategies during semen transport. The development of antioxidant-enriched semen extenders, packaging and shielding system improvements, and controlled field trials replicating real airport exposure conditions represent promising avenues for reducing radiation-related risks. Ensuring the integrity of transported semen is essential for maintaining reproductive success and supporting the global distribution of superior genetic material in livestock breeding programs.

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Acknowledgments

The author expresses gratitude to the Rector of Airlangga University, the Dean of the Faculty of Veterinary Medicine, and the Coordinator of the Doctoral Program in Veterinary Science at Airlangga University for their support in providing facilities and unlimited library access.

Conflict of interest

The authors declare no conflict of interest.

Funding

This work was supported by the Indonesian Education Scholarship (BPI), the Center for Higher Education Funding and Assessment (PPAPT), the Ministry of Higher Education, Science, and Technology of the Republic Indonesia, and the Endowment Fund for Education Agency (LPDP), the Ministry of Finance of the Republic of Indonesia.

Authors' contributions

The collection of literature was carried out by A.A.G.O.D. and B.S.L. Data were curated by A.A.G.O.D., I.K.P., and I.W.N.G. Formal analysis was performed by A.A.G.O.D. and I.K.P. The project’s resources were provided by I.W.N.G., W.M.Y., and B.S.L. Supervision was undertaken by W.M.Y. and B.S.L., with validation performed by I.K.P. and W.M.Y. The original draft was written by A.A.G.O.D., and the review and editing process was completed by I.K.P., I.W.N.G., W.M.Y., and B.S.L.

Data availability

All data were provided in the manuscript.

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