Aminoguanidine Protects Boar Spermatozoa against the Deleterious Effects of Oxidative Stress

Abstract

Aminoguanidine is a selective inhibitor of the inducible nitric oxide synthase (iNOS) and a scavenger of reactive oxygen species (ROS). Numerous studies have shown the antioxidant properties of aminoguanidine in several cell lines, but the in vitro effects of this compound on spermatozoa under oxidative stress are unknown. In this study, we tested the hypothesis that aminoguanidine may protect against the detrimental effects of oxidative stress in boar spermatozoa. For this purpose, sperm samples were incubated with a ROS generating system (Fe2+/ascorbate) with or without aminoguanidine supplementation (10, 1, and 0.1 mM). Our results show that aminoguanidine has powerful antioxidant capacity and protects boar spermatozoa against the deleterious effects of oxidative stress. After 2 h and 3.5 h of sperm incubation, the samples treated with aminoguanidine showed a significant increase in sperm velocity, plasma membrane and acrosome integrity together with a reduced lipid peroxidation in comparison with control samples (p < 0.001). Interestingly, except for the levels of malondialdehyde, the samples treated with 1 mM aminoguanidine did not differ or showed better performance than control samples without Fe2+/ascorbate. The results from this study provide new insights into the application of aminoguanidine as an in vitro therapeutic agent against the detrimental effects of oxidative stress in semen samples.

Pharmacological Activity of Honeybush (Cyclopia intermedia) in Boar Spermatozoa during Semen Storage and under Oxidative Stress

“…The ROS generating system employed in this study promotes a decrease in sperm motility and kinetic parameters, together with an increase in MDA levels in the semen samples, as previously reported [16]. Our results clearly show that the honeybush extract mitigates the negative effects of oxidative stress on boar spermatozoa.…”

“…One of them was used as a control (CTR). In the remaining tubes, oxidative stress was induced by 0.05 mM FeSO 4 and 0.5 mM sodium ascorbate (Fe 2+ /ascorbate), as previously described [16]. One of the tubes was used as a control (CTR-ox), while the rest of the tubes were supplemented with the honeybush extract.…”

“…Then, the spermatozoa were assessed under epi-fluorescence microscopy (Nikon Eclipse E600, Nikon, Japan; 400× magnification), and those with a complete green fluorescence over the head were considered to have an intact plasma membrane. For the acrosomal status, the percentage of sperm with a normal apical ridge (NAR [18]) was determined as previously described [16,19]. Briefly, the sperm samples were fixed in a glutaraldehyde solution (2%) and evaluated under phase contrast microscopy (400× magnification).…”

“…The lipid peroxidation was assessed using the thiobarbituric acid reactive substances (TBARS) assay, as previously described [16,21]. After 4 h of incubation at 17 • C, the sperm aliquots were collected and stored at −80 • C, until the analysis.…”

The Roles of NO and H2S in Sperm Biology: Recent Advances and New Perspectives

“…As a free radical, increased concentrations of NO within the sperm cell are associated with male infertility [79]. In this way, aminoguanidine, an NOS inhibitor, protects the sperm cells against the detrimental consequences of oxidative stress both in vivo and in vitro [82,83]. Yet, it should be mentioned that NO may also stop radical chain propagation through interaction with the lipid peroxyl radical (an intermediate of lipid peroxidation) to form oxidized forms of nitrosated fatty acid species [84].…”