Vitamin E Delivery Systems Increase Resistance to Oxidative Stress in Red Deer Sperm Cells: Hydrogel and Nanoemulsion Carriers

Abstract

Oxidative stress has become a major concern in the field of spermatology, and one of the possible solutions to this acute problem would be the use of antioxidant protection; however, more studies are required in this field, as highly contradictory results regarding the addition of antioxidants have been obtained. Vitamin E is a powerful biological antioxidant, but its low stability and high hydrophobicity limit its application in spermatology, making the use of organic solvents necessary, which renders spermatozoa practically motionless. Keeping this in mind, we propose the use of hydrogels (HVEs) and nanoemulsions (NVEs), alone or in combination, as carriers for the controlled release of vitamin E, thus, improving its solubility and stability and preventing oxidative stress in sperm cells. Cryopreserved sperm from six stags was thawed and extended to 30 × 106 sperm/mL in Bovine Gamete Medium (BGM). Once aliquoted, the samples were incubated as follows: control, free vitamin E (1 mM), NVEs (9 mM), HVEs (1 mM), and the combination of HVEs and NVEs (H + N), with or without induced oxidative stress (100 µM Fe2+/ascorbate). The different treatments were analyzed after 0, 2, 5, and 24 h of incubation at 37 °C. Motility (CASA®), viability (YO-PRO-1/IP), mitochondrial membrane potential (Mitotracker Deep Red 633), lipid peroxidation (C11 BODIPY 581/591), intracellular reactive oxygen species production (CM-H2DCFDA), and DNA status (SCSA®) were assessed. Our results show that the deleterious effects of exogenous oxidative stress were prevented by the vitamin E-loaded carriers proposed, while the kinematic sperm parameters (p ˂ 0.05) and sperm viability were always preserved. Moreover, the vitamin E formulations maintained and preserved mitochondrial activity, prevented sperm lipid peroxidation, and decreased reactive oxygen species (ROS) production (p ˂ 0.05) under oxidative stress conditions. Vitamin E formulations were significantly different as regards the free vitamin E samples (p < 0.001), whose sperm kinematic parameters drastically decreased. This is the first time that vitamin E has been formulated as hydrogels. This new formulation could be highly relevant for sperm physiology preservation, signifying an excellent approach against sperm oxidative damage.

Vitamin E Lipid-Based Nanodevices as a Tool for Ovine Sperm Protection against Oxidative Stress: Impact on Sperm Motility

“…NE were obtained following published procedures [ 29 ] and characterized by using Dynamic light scattering (DLS) measurements. NE formulations displayed an average particle size of 159 ± 1.4 nm and a polydispersity index (PDI) of 0.118 ± 0.146.…”

“…Nevertheless, its application in assisted reproduction is restricted due to the toxicity of the organic solvents required for administration [ 14 , 15 , 17 , 18 , 28 ]. The use of Vitamin E delivery systems, such as nanoemulsions [ 22 , 29 ] or hydrogels [ 29 ], offers several advantages in comparison to conventional administration. The beneficial effects of these nanodevices comprise improvement to sperm motility parameters with respect to free VE, reduction in ROS production and lipid peroxidation under oxidative stress conditions.…”

“…Recently, we reported lipid-based VE nanodevices as a tool for preserving red deer post-thawed sperm samples against oxidative stress [ 29 ]. This report was a pioneering work in assisted reproduction technologies in which vitamin E nanodevices were tested in ram spermatozoa, as a proof of concept.…”

Structure‒function‒pathogenicity analysis of C-terminal myocilin missense variants based on experiments and 3D models

“…Cellular oxidative injury was evaluated by detecting reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP). The generation of ROS was measured by the DCFH-DA probe (Beyotime, Cat#S0033S), and MMP was detected by the Mito-Tracker Red CMXRos probe (Beyotime, Cat#C1049) according to the manufacturers’ instruction and previous studies ( Jurado-Campos et al, 2021 ; Gu et al, 2022 ). Briefly, cells were cultured and treated in 24-well plates, and incubated with corresponding probes at 37°C in the dark for 30 min.…”

Extend the Survival of Human Sperm In Vitro in Non-Freezing Conditions: Damage Mechanisms, Preservation Technologies, and Clinical Applications

“…Except for inorganic metal elements, some organic substances play protective roles in sperm preservation and can be prepared as nanoformulations that overcome their limitations such as low stability and hydrophobicity. A vitamin E delivery system using nanoemuisions carriers showed significantly better sperm preservation effects compared with free vitamin E [ 277 ]. Nanosized curcumin extracts, lecithin can also be added into extenders to improve the cryosurvival of animal sperm [ 278 , 279 ].…”