Supplementation of Plant-Based Cryopreservation Medium with Folic Acid Conserves the Quality of Bulk Post-Thawed Spermatozoa.

The current study evaluated the effects of cryopreservation medium supplementation with folic acid as an antioxidant on post-thawed semen quality in bulk. Semen samples were collected from four proved Iranian Mahabadi bulls and diluted in extender containing 1.5% soybean lecithin. The diluted semen was assigned into six parts and supplemented with different doses of folic acid as follows: FA0 (extender without folic acid), FA0.05, FA0.1, FA0.2, FA0.4, and FA0.8 (extenders containing 0.05, 0.1, 0.2, 0.4, and 0.8 mM folic acid, respectively). Then, the semen samples were cryopreserved in liquid nitrogen. Sperm motility and velocity parameters, membrane integrity, abnormal morphology, viability, and lipid peroxidation were evaluated after thawing. In the results, FA0.05 presented higher (p≤0.05) total motility, progressive motility, membrane integrity, and viability and lower lipid peroxidation compared to other groups. Abnormal morphology was not affected (p>0.05) by treatments. In conclusion, supplementation of cryopreservation medium with 0.05 mM folic acid is a helpful method to conserve the quality of post-thawed semen in bulk.

The effect of adding pyridoxine to soybean lecithin-based extender on goat semen quality parameters after the freeze-thawing process.

BACKGROUND: Supplementing the semen extender with various antioxidants can increase the quality of semen. AIMS: The aim of the present study was to investigate the addition of pyridoxine (vitamin B6), a phenolic compound with antioxidant properties, to soybean lecithin extender on motility and quality indices of goat sperm after freezing-thawing process. METHODS: Semen was collected at weekly intervals from four Mahabadi goats, mixed, and was divided into 7 subsamples. They were then diluted with the basal extender supplemented with 0, 2, 4, 6, 8, 10, and 12 mM pyridoxine. Following freeze-thawing process, quality parameters such as sperm motility characteristics, viability, plasma membrane integrity, and malondialdehyde content were determined. RESULTS: The results showed that pyridoxine at the level of 6 mM caused the highest total motility rate (P<0.05). Progressive sperm motility was highest at the 4, 6, and 8 mM pyridoxine (P<0.05). Although the control group showed the least progressive motility, it was not statistically significantly different from the 12 mM level. Among the pyridoxine levels, the 6 mM level recorded the best performance in term of plasma membrane integrity, sperm viability, and decreasing malondialdehyde concentration compared to the control group (P<0.05). CONCLUSION: The findings indicated that soybean lecithin extender supplemented with 6 mM pyridoxine can improve motility and quality parameters such as viability, plasma membrane integrity, and reduce oxidative stress of goat sperm after thawing.

The effect of Tempo and MitoTEMPO on oocyte maturation and subsequent embryo development in bovine model.

Reactive oxygen species (ROS) are one of the factors which reduces oocyte quality and viability of the in vitro produced embryos. Oocyte mitochondria are the major source of ROS production, hence, and the addition of mitochondrion-specific antioxidants could be suggested to minimize the damage caused by ROS during culture. MitoTEMPO, a targeted mitochondrial antioxidant, is formed by conjugating TEMPO to triphenylphosphonium and has an activity like that of superoxide dismutase. It can pass through lipid bilayers easily and accumulate selectively in mitochondria. The goal of this study was to investigate the effects of MitoTEMPO and its non-targeted form, TEMPO, on the developmental competence of bovine oocytes. Accordingly, oocytes were cultured in maturation medium supplemented with either five mM TEMPO (T5) or one µM MitoTEMPO (M1), or T5 + M1 (MT15), or without the antioxidants (C). Nuclear maturation to metaphase II (MII) stage, intracellular glutathione (GSH) content and ROS levels in matured oocytes were analyzed. In addition, cleavage after in vitro fertilization, and blastocyst rates, total cell number in blastocysts as well as the relative abundance of apoptosis-related genes (BAX and BCL2) in blastocysts were determined. Results revealed that the proportion of oocytes at the MII stage, embryos at the blastocyst stage and total cell number in blastocysts increased significantly in the M1 group compared to the C and T5 groups. The levels of intracellular GSH and ROS in oocytes decreased in the M1 group than in the C group (P < 0.05). The expression level of the pro-apoptotic gene (BAX) reduced in blastocysts from the M1 group in comparison to the C and T5 groups (P < 0.05). On the other hand, the expression level of anti-apoptotic gene (BCL2) in obtained blastocysts was not affected by TEMPO and MitoTEMPO. However, the ratio of BAX/BCL2 in blastocysts from the M1 and MT15 groups decreased significantly compared to the C group. These findings suggest that MitoTEMPO can mitigate the adverse effects of oxidative stress on the developmental competence of bovine oocytes.

Optical bistability in coupled optomechanical cavities in the presence of Kerr effect.

We theoretically investigate optical bistability for a hybrid optomechanical system, where two cavities (an optomechanical cavity and a traditional one) are coupled together. A Kerr medium is inserted in the optomechanical cavity and there is an ultra-cold atomic gas inside the other. Dynamics of the system is described by Heisenberg-Langevin equations of motion in the steady-state regime. Bistability is observed in intracavity intensity for the optomechanical cavity, and the response of this phenomenon to optical parameters of the system is investigated. It is observed that the atomic medium has a deep effect on bistable behavior of intracavity intensity for the optomechanical cavity. Also, we determine a critical value for the Kerr coefficient of the Kerr medium to observe bistability in intracavity intensity for the optomechanical cavity.

Antioxidant effects of clove bud (Syzygium aromaticum) extract used with different extenders on ram spermatozoa during cryopreservation.

Clove bud (Syzygium aromaticum) extract was added at concentrations of 0, 35, 75, and 115 µg/ml to ovine semen extenders in order to investigate the antioxidant activities of clove bud extract and its effects on semen quality parameters after cryopreservation of ram spermatozoa. The basic extender was composed of Tris, egg yolk, and glycerol. Two other extenders were prepared by substitution of egg yolk with either LDL or egg yolk+SDS. The DPPH inhibition test was employed to assess the antioxidant activity of clove bud extract. Results showed that, compared to vitamin E, clove bud extract had a higher antioxidant activity. Better sperm motility and movement characteristics (P<0.05) were observed in the semen diluted with medium containing egg yolk+SDS than in that containing egg yolk and LDL. Progressive motility and movement characteristics of the sperm were significantly improved (P<0.05) by adding 35 and/or 75 µg/ml of clove bud extract to semen extenders. Sperm viability and plasma membrane integrity were also higher (P<0.05) in the semen exposed to medium containing egg yolk+SDS and 75 µg of clove buds extract after cryopreservation processes. Higher levels of clove bud extract, however, had adverse effects on all the sperm quality parameters and significantly reduced (P<0.05) the motility, movement parameters, viability, and plasma membrane integrity of ovine sperm. It was concluded that the clove bud extract had an antioxidant potential that makes it useful for addition to semen extenders and that the best results are obtained with a maximum clove bud extract of 75 µg/ml. Moreover, the combination of egg yolk and a detergent was found to improve sperm quality after the cooling and freeze-thawing processes.