Do Linalool-Loaded Solid Lipid Nanoparticles Improve the Quality of Naval Medical Research Institute Mouse Sperm During Freezing/Thawing and Handling Processes?

Abstract

Introduction: Handling, freezing, and thawing of sperm causes oxidative stress, compromising sperm quality. Nanotechnology offers platforms for the smart delivery of antioxidants during these processes. Objectives: A solid lipid nanoparticle (SLN) was used to deliver linalool, as an antioxidant supplementation to Naval Medical Research Institute mouse sperm during handling, freezing, and thawing. Methods: Linalool-loaded solid lipid nanoparticle (L-SLN) was made using the self-assembly method. After the assessment of physicochemical properties, the impact of L-SLN (10, 20, 30, and 50 µg/mL) on sperm motility, viability, sperm DNA fragmentation (SDF), nitric oxide (NO) production, and the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT), was investigated after its addition to the handling, freezing, and thawing media. Results: L-SLN was successfully created with a size of 262 ± 9.5 and a zeta potential of -28.5 ± 7.12, with an extended-release over time. During handling and freezing, supplementing corresponding media with L-SLN resulted in increased sperm motility and viability, specifically at 30 µg/mL. The percentage of SDF also decreased in post-thawed sperm at 30 µg/mL. L-SLN also led to elevated post-thawed NO production at 20 µg/mL, as well as increased SOD activity at 20 and 30 µg/mL. It also enhanced CAT and GPx activity at 30 and 10 µg/mL respectively. In handling media, L-SLN at 10 µg/mL could enhance NO production, CAT, and SOD activity, and at 20 µg/mL also boosted NO production and GPx activity. Generally, there was no significant improvement in sperm parameters with the mutual concentration of L-SLN for thawing media. Conclusions: Treating sperm extender media with 20 and 30 µg/mL of L-SLN and handling media with 10 and 30 µg/mL of L-SLN could improve sperm parameters following these interventions. L-SLN is a new antioxidant for sperm handling and freezing media, which may be applicable in human reproductive efforts.