Tvrdá E., Greifová H., Mackovich A., Hashim F., Lukáč N. (2018): Curcumin offers antioxidant protection to cryopreserved bovine semen. Czech J. Anim. Sci., 63,[247][248][249][250][251][252][253][254][255] Evidence shows that oxidative stress associated with sperm cryopreservation may lead to a significant decrease of the structural integrity and functional activity of male gametes. Curcumin (CUR) has become a substance of scientific interest for its free radical-quenching abilities, which could enhance the post-thaw quality of male gametes. This study assessed the effects of CUR on the post-thaw vitality and selected oxidative stress markers of bovine spermatozoa. Thirty ejaculates collected from 10 breeding bulls were divided into two aliquots and cryopreserved in the absence (control) or presence of CUR (50 μmol/l). Immediately before use, the control or experimental straws were thawed at 37°C for 20 s. CUR administration led to a significantly higher preservation of spermatozoa motion (P < 0.001) as well as membrane (P < 0.05) and acrosomal (P < 0.01) integrity in comparison with the control. Moreover, spermatozoa exposed to CUR exhibited a significantly higher mitochondrial activity (P < 0.001). Significantly decreased amounts of reactive oxygen species (P < 0.01) and superoxide (P < 0.001) were detected following CUR supplementation. Finally, a significant decrease of oxidative damage to proteins (P < 0.01), lipids (P < 0.001), and DNA (P < 0.05) was recorded in samples to which CUR was administered in comparison to the control. In this study, CUR proved to act as an efficient antioxidant molecule offering protection to male gametes against oxidative damage during cryopreservation.

Reactive oxygen species overgeneration as a side effect of semen cryopreservation may lead to lipid peroxidation, protein degradation, DNA fragmentation and cell death, resulting in a decrease of sperm survival and fertilisation ability. Lycopene has been proposed as a potential supplement to semen extenders because of its antioxidant properties. The aim of this study was to evaluate the effects of lycopene on the structural integrity, functional activity and selected oxidative stress parameters of cryopreserved bovine sperm. Thirty bovine ejaculates were split into two aliquots and diluted with a commercial semen extender supplemented with 1.5 mmol/l lycopene or containing no supplement (control), cooled down to 4 °C, frozen and kept in liquid nitrogen. Prior to experiments, frozen straws were thawed at 37 °C for 20 s. Lycopene addition resulted in a higher sperm motility (P &lt; 0.001), progressive motility (P &lt; 0.001) and all secondary motion characteristics (P &lt; 0.001 with respect to the average path velocity, linear velocity, velocity of curvilinear motion, beat cross frequency, path straightness and linearity; P &lt; 0.01 in the case of the amplitude of lateral head displacement). Furthermore, lycopene exhibited protective effects on the sperm membrane (P &lt; 0.05) and acrosomal (P &lt; 0.01) integrity in comparison to control. An assay for metabolic function revealed that lycopene supplementation to the cryopreservation medium resulted in a higher preservation of the sperm mitochondrial activity (P &lt; 0.001). Reactive oxygen species production as well as intracellular superoxide generation were decreased following lycopene addition (P &lt; 0.01 in the case of reactive oxygen species; P &lt; 0.001 with respect to superoxide production). Finally, the presence of lycopene led to a decrease in protein carbonyl production (P &lt; 0.01), lipid peroxidation (P &lt; 0.001) as well as oxidative DNA damage (P &lt; 0.05) when compared to control. In conclusion, lycopene exhibited significant reactive oxygen species-trapping and antioxidant properties which may prevent oxidative damage to frozen-thawed sperm, and, thus, enhance the post-thaw vitality of male reproductive cells in cattle breeding.

The aim of this study was to assess the dose- and time dependent in vitro effects of resveratrol (RES), a natural polyphenol and phytoalexin with potential antiviral, anti-inflammatory and antioxidant properties on bovine spermatozoa during five different time periods (0h, 2h, 6h, 12h and 24h). Semen samples were collected from 20 adult breeding bulls, and diluted in physiological saline solution containing 0.5% DMSO together with 0, 1, 5, 10, 50, 100 and 200 μM/L RES. Spermatozoa motility was examined using the Sperm VisionTM and CASA (Computer Assisted Semen Analyzer) system. Cell viability was measured using the metabolic activity MTT assay, the nitroblue-tetrazolium (NBT) test was used to assess the intracellular superoxide formation. The initial CASA analysis showed no significant changes in the spermatozoa motion parameters, however a motion-promoting effect of 10 and 50 μM/L RES became significant after 2h (P

The aim of this short review is to investigate the effects of biological active substances namely vitamin C and E, Quercetin, Tannic acid, Lycopene, Resveratrol, and Curcumin to viability and cryopreservation of spermatozoa; as well as the sensitivity of spermatozoa to reactive oxygen species and the strategies how to avoid oxidative stress (OS) by using naturally occurring antioxidants mentioned above. The oxidative stress, which has been associated with male infertility and many degenerative diseases, can be reduced by antioxidants via breaking the oxidative chain reactions. Lycopene is one the most highly efficient antioxidant and free radical scavenger and has protective effect on spermatozoa. Trans-Resveratrol also has positive effects on the production of spermatozoa. Consequently, one of the most prominent compounds “curcumin” which has widely been studied for its anti-inflammatory, anti-angiogenic, antioxidant, wound healing and anti-cancer effects; as well as showed energy-promoting and protective effects on the testicular tissue and spermatogenesis.

To preserve and protect spermatozoa against any possible oxidative damage the addition of natural antioxidants might be the ideal solution which has been investigated worldwide. The composition of the diluents is as follows: 50 µM/L vitamin C with 0.5% DMSO (dimethyl sulfoxide, Sigma, St. Louis, USA); 50 µM/L vitamin E with 0.5% ethanol; each added separately to the spermatozoa with the aim to determine its effect on post-thaw quality of spermatozoa. 20 samples from each control and experimental group were analysed. Semen was thawed at 37°C for 70 seconds. The sperm motility parameters were analysed immediately after thawing used Sperm Vision CASA (Computer Assisted Semen Analysis) system. The viability of the cells was evaluated by metabolic activity MTT assay and the nitroblue-tetrazolium (NBT) test was used to assess the intracellular formation of the superoxide radicals. Motility was observed with highest statistical differences (P0.05) with the samples containing vitamin C, however, higher percentage (54%) of motility was observed in comparison to the control group (51.61%). Based on MTT assay, viability was also improved with the supplementation of vitamin C with the highest significance (P0.05). however, had higher percentage of viable spermatozoa (105.8%) when compare to the control group (100.1%) which did not contain vitamin E. All of the mentioned substances used – vitamin C, vitamin E – prevented the intracellular overproduction of free radicals within the sperm mitochondrial membrane with the statistical significance (P