Cryopreservation and oxidative stress in porcine oocytes

Gentile di Puglia (GdP) is an autochthonous sheep breed of Southern Italy included among ovine breeds threatened by genetic erosion and extinction risk, which have been given attention by local and international institutions, thus emphasizing the need for germplasm conservation actions. In the present study, two assisted reproduction approaches, finalized for GdP conservation, were performed: (1) on-farm reproductive efficiency evaluation, expressed as pregnancy rate (PR), twin pregnancy rate (tPR), and body condition score (BCS), for three consecutive breeding cycles and (2) pre-pubertal lambs’ immature cumulus–oocyte complex (COC) retrieval, vitrification, in vitro maturation (IVM), and assessment of meiotic stage and bioenergetic-oxidative status compared with those of other Italian and European commercial breeds. PR and tPR were progressively reduced over time. In all clinical examination times, BCS was significantly lower in nonpregnant ewes compared with pregnant ones. Fresh GdP pre-pubertal lamb COCs achieved meiotic maturation and showed healthy bioenergetic–oxidative status after IVM. Vitrification reduced the oocyte maturation rate in all groups. However, mature oocytes retained their cytoplasmic maturity, expressed as a mitochondria distribution pattern and activity, indicating promising developmental competence. In conclusion, clinical- and biotechnological-assisted reproduction approaches can support conservation strategies of GdP and other local sheep breeds in Southern Italy.

Section: Discussionmentioning

confidence: 89%

New Strategies for Conservation of Gentile di Puglia Sheep Breed, an Autochthonous Capital of Millennial Tradition in Southern Italy

Temerario

Monaco

Mastrorocco

et al. 2023

“…The cryopreservation of mouse [ 27 ], bovine [ 50 ], pig [ 51 ], and human oocytes [ 52 ] increases oxidative stress, although exogenous melatonin reduce oxidative stress in vitrified-warmed oocytes [ 30 , 53 ]. The Nrf2 signaling pathway is an important intracellular antioxidant signaling pathway, critical for maintaining redox balance [ 31 , 54 ].…”

Section: Discussionmentioning

confidence: 99%

Melatonin Promotes In Vitro Maturation of Vitrified-Warmed Mouse Germinal Vesicle Oocytes, Potentially by Reducing Oxidative Stress through the Nrf2 Pathway

Guo

Yang

Qin

et al. 2021

Previously it was reported that melatonin could mitigate oxidative stress caused by oocyte cryopreservation; however, the underlying molecular mechanisms which cause this remain unclear. The objective was to explore whether melatonin could reduce oxidative stress during in vitro maturation of vitrified-warmed mouse germinal vesicle (GV) oocytes through the Nrf2 signaling pathway or its receptors. During in vitro maturation of vitrified-warmed mouse GV oocytes, there were decreases (p < 0.05) in the development rates of metaphase I (MI) oocytes and metaphase II (MII) and spindle morphology grades; increases (p < 0.05) in the reactive oxygen species (ROS) levels; and decreases (p < 0.05) in expressions of Nrf2 signaling pathway-related genes (Nrf2, SOD1) and proteins (Nrf2, HO-1). However, adding 10−7 mol/L melatonin to both the warming solution and maturation solutions improved (p < 0.05) these indicators. When the Nrf2 protein was specifically inhibited by Brusatol, melatonin did not increase development rates, spindle morphology grades, genes, or protein expressions, nor did it reduce vitrification-induced intracellular oxidative stress in GV oocytes during in vitro maturation. In addition, when melatonin receptors were inhibited by luzindole, the ability of melatonin to scavenge intracellular ROS was decreased, and the expressions of genes (Nrf2, SOD1) and proteins (Nrf2, HO-1) were not restored to control levels. Therefore, we concluded that 10−7 mol/L melatonin acted on the Nrf2 signaling pathway through its receptors to regulate the expression of genes (Nrf2, SOD1) and proteins (Nrf2, HO-1), and mitigate intracellular oxidative stress, thereby enhancing in vitro development of vitrified-warmed mouse GV oocytes.

“…Additionally, vitrification has been shown to induce parthenogenic activation at a high rate (approximately 50%) when oocytes are vitrified at the mature stage [108]. Disruption of cellular functions, especially mitochondrial activities, after vitrification leads to increased reactive oxygen species levels and results in cell apoptosis [109][110][111]. Therefore, the application of antioxidants such as astaxanthin [112] and caspase inhibitor [113] decreased apoptosis and improved the development of vitrified-warmed oocytes.…”

Section: Pigmentioning

confidence: 99%

Oocyte Cryopreservation in Domestic Animals and Humans: Principles, Techniques and Updated Outcomes

Tharasanit

Thuwanut

2021

Oocyte cryopreservation plays important roles in basic research and the application of models for genetic preservation and in clinical situations. This technology provides long-term storage of gametes for genetic banking and subsequent use with other assisted reproductive technologies. Until recently, oocytes have remained the most difficult cell type to freeze, as the oocytes per se are large with limited surface area to cytoplasm ratio. They are also highly sensitive to damage during cryopreservation, and therefore the success rate of oocyte cryopreservation is generally poor when compared to noncryopreserved oocytes. Although advancement in oocyte cryopreservation has progressed rapidly for decades, the improvement of cryosurvival and clinical outcomes is still required. This review focuses on the principles, techniques, outcomes and prospects of oocyte cryopreservation in domestic animals and humans.