Dendrobine enhances bovine oocyte maturation and subsequent embryonic development and quality.

Strategies for improving the quality of oocytes have important theoretical and practical significance for increasing the efficiency of livestock breeding. In this respect, the accumulation of reactive oxygen species (ROS) is a major factor affecting the development of oocytes and embryos. This study investigated the effects of Dendrobium nobile extract (DNE) on the in vitro maturation of bovine oocytes and embryonic development after IVF. DNE is an extract from Dendrobium rhizomes that contains alkaloids with anti-inflammatory, anti-cancer and anti-ageing functions. Various concentrations of DNE (0, 5, 10, 20 and 50 µmol/L) were added during oocyte maturation in vitro, and we found that 10 µmol/L of DNE remarkably increased the oocyte maturation rate, the subsequent blastocyst formation rate and embryo quality. Further, we found that DNE treatment decreased the frequency of spindle/chromosome defects and ROS and increased the oocyte glutathione and mitochondrial membrane potential in oocytes. Moreover, DNE upregulated the expression of oxidative stress-related genes (Sirt1, Sirt2, Sirt3 and Sod1) in oocytes and apoptosis-related genes (Caspase-3, Caspase-4, Bax, Bcl-xl and Survivin) in blastocysts. These results suggest that DNE supplementation can promote oocyte maturation and subsequent embryonic development by regulating redox reactions and inhibiting embryonic apoptosis.

Glyphosate decreases bovine oocyte quality by inducing oxidative stress and apoptosis.

Glyphosate is a universal herbicide with genital toxicity, but the effect of glyphosate on oocytes has not been reported. This study aimed to evaluate the effect of glyphosate (0, 10, 20, 50 and 100 mM) on bovine oocyte in vitro maturation. We showed that 50 mM glyphosate adversely affects the development of bovine oocytes. Exposure of oocytes to 50 mM glyphosate caused an abnormal reduction in oxidative (redox) levels compared with that in the control group, with a significantly higher reactive oxide species level (P < 0.05) and significantly lower glutathione (GSH) expression (P < 0.05). Additionally, the mRNA levels of antioxidant genes (SOD1, SOD2, SIRT2, SIRT3) and the mitochondrial membrane potential (MMP) were significantly reduced (P < 0.05). Furthermore, treatment with 50 mM glyphosate-induced apoptosis, and the mRNA levels of the apoptotic genes Caspase-3 and Caspase-4 were significantly higher than those in the control group (P < 0.05); however, the mRNA level of BAX was significantly higher than that in the control group (P < 0.01). Additionally, the mRNA levels of the anti-apoptotic genes Survivin and BCL-XL were significantly lower than those in the control group (P < 0.05), and oocyte quality was adversely affected. Together, our results confirmed that glyphosate impairs the quality of oocytes by promoting abnormal oocyte redox levels and apoptosis.

Supplementation of kaempferol to in vitro maturation medium regulates oxidative stress and enhances subsequent embryonic development in vitro.

Kaempferol (KAE) is one of the most common dietary flavonols possessing biological activities such as anticancer, anti-inflammatory and antioxidant effects. Although previous studies have reported the biological activity of KAE on a variety of cells, it is not clear whether KAE plays a similar role in oocyte and embryo in vitro culture systems. This study investigated the effect of KAE addition to in vitro maturation on the antioxidant capacity of embryos in porcine oocytes after parthenogenetic activation. The effects of kaempferol on oocyte quality in porcine oocytes were studied based on the expression of related genes, reactive oxygen species, glutathione and mitochondrial membrane potential as criteria. The rate of blastocyst formation was significantly higher in oocytes treated with 0.1 µm KAE than in control oocytes. The mRNA level of the apoptosis-related gene Caspase-3 was significantly lower in the blastocysts derived from KAE-treated oocytes than in the control group and the mRNA expression of the embryo development-related genes COX2 and SOX2 was significantly increased in the KAE-treated group compared with that in the control group. Furthermore, the level of intracellular reactive oxygen species was significantly decreased and that of glutathione was significantly increased after KAE treatment. Mitochondrial membrane potential (ΔΨm) was increased and the activity of Caspase-3 was significantly decreased in the KAE-treated group compared with that in the control group. Taken together, these results suggested that KAE is beneficial for the improvement of embryo development by inhibiting oxidative stress in porcine oocytes.