Protective effects of exogenous gangliosides on ROS-induced changes in human spermatozoa.

This article summarizes the available evidence on the efficacy of gangliosides to reduce the degree of reactive oxygen species (ROS)-mediated damage. The antioxidative efficacy of exogenous gangliosides in protecting different cells encouraged us to examine their ability to protect human spermatozoa. Gangliosides are sialic acid-containing glycosphingolipids with strong amphiphilic character due to the bulky headgroup made of several sugar rings with sialic acid residues and the double-tailed hydrophobic lipid moiety.

Protective effect of gangliosides on DNA in human spermatozoa exposed to cryopreservation.

Gangliosides, the sialic acid-containing glycosphyngolipids, are amphiphilic compounds which in micellar form affect the properties and functions of a cellular membrane. The aim of this study was to test whether exogenous gangliosides supplied to cryopreservation media before freezing could protect sperm cells from cryopreservation-induced DNA damage assessed by Comet assay. Additionally, to investigate whether gangliosides were also able to reduce membrane integrity damage, malonaldialdehyde as a measure of lipid peroxidation and sperm-specific lactate dehydrogenase-C4 activity as an enzyme marker of sperm membrane leakage were determined.

Ganglioside GT1b protects human spermatozoa from hydrogen peroxide-induced DNA and membrane damage.

We have reported previously that various gangliosides, the sialic acid containing glycosphingolipids, provide protection against sperm injury caused by reactive oxygen species (ROS). In this study, we investigated the effect of treatment of human spermatozoa with ganglioside GT1b on hydrogen peroxide (H(2)O(2))-induced DNA fragmentation and plasma membrane damage. Single-cell gel electrophoresis (Comet assay) used in the assessment of sperm DNA integrity showed that in vitro supplemented GT1b (100 microm) significantly reduced DNA damage induced by H(2)O(2) (200 microm) (p < 0.

Antioxidant properties of ganglioside micelles.

Antioxidant activity of gangliosides GM1 and GT1b in the Fenton type of reaction was investigated by EPR spectroscopy using DMPO as a spin trap. Hydroxyl radical spin adduct signal intensity was significantly reduced in the presence of gangliosides at their micellar concentrations. Mean micellar hydrodynamic diameter was not changed, whereas significant changes in negative Zeta potential values were observed as evidenced by Zetasizer Nano ZS.

Trisialoganglioside GT1b prevents increase in sperm membrane molecular ordering induced by in vitro lipid peroxidation.

The effect of various types of gangliosides, the sialic acid-containing glycosphingolipids, on human sperm membrane during lipid peroxidation induced by Fe(2+)/ascorbate ions was investigated. The monosialoganglioside (GM1), disialogangliosides (GD1a and GD1b), and trisialoganglioside (GT1b) were examined at a concentration of 100 microM, which was above their respective critical micellar concentrations. Lipid peroxidation was determined by quantification of malondialdehyde (MDA) concentration.

Effect of gangliosides on the copper-induced oxidation of human low-density lipoproteins.

The role of gangliosides in the copper-induced oxidative modification of human low-density lipoprotein (LDL) was studied focusing on the early stage of LDL oxidation in which the concentration of conjugated dienes increases only weakly. The changes in the protein and lipid component were followed using fluorescence spectroscopy. The results indicate that binding of gangliosides to LDL causes slower destruction of tryptophan fluorescence and suppresses cross-linking between the reactive groups of the protein and the products of lipid peroxidation.

Age-associated alteration of lipid peroxidation and superoxide dismutase activity in CBA and AKR mice.

Oxidative modification of lipids, proteins and DNA by reactive oxygen species in the organism and imbalance between the concentrations of free radicals and the antioxidant defenses may be related to processes such as aging and diseases (cardiovascular, neurodegenerative, cancer, etc.). Although the relationship between oxidant status and antioxidant defence in aging of different species, organs or sexes has been investigated extensively, the studies have produced conflicting results.