Epigallocatechin-3-gallate protects porcine oocytes against post-ovulatory aging through inhibition of oxidative stress

Abstract

Increased levels of oxidative stress are major factors that drive the process of post-ovulatory oocyte aging. Epigallocatechin-3-gallate (EGCG), which accounts for up to 50% of the catechins, possesses versatile biological functions, including preventing or treating diabetes, cancer, and heart diseases. The aim of this study was to explore whether EGCG can delay porcine oocyte aging by preventing oxidative stress. Metaphase II (MII) oocytes were cultured for 48 h with different concentrations of EGCG (0–100 μM) in vitro as a post-ovulatory aging model. An optimal concentration of 5 μM EGCG maintained oocyte morphology and developmental competence during aging. The oocytes were randomly divided into five groups: fresh, 24 h control, 24 h EGCG, 48 h control, and 48 h EGCG. The results suggest that EGCG significantly prevents aging-induced oxidative stress, glutathione (GSH) reduction, apoptosis, and autophagy. Moreover, mitochondria DNA copy number was decreased, and the number of active mitochondria and adenosine triphosphate (ATP) levels significantly increased by supplementation with EGCG. Thus, EGCG has a preventive role against aging in porcine post-ovulatory oocytes due to its ability to inhibit oxidative stress and promote mitochondrial biogenesis.

Epigallocatechin‐3‐gallate improves the quality of maternally aged oocytes

“…These interventions have demonstrated the potential to enhance oocyte quality and alleviate infertility, particularly in aged rodent models. As an antioxidant, EGCG at relatively low concentrations has shown a protective effect on oocyte quality across various species 20,23,25 . However, higher concentrations of EGCG can lead to pro‐oxidative effects.…”

“… 20 For instance, the administration of EGCG at a lower concentration significantly improved the oocyte maturation and blastocyst development in bovine, 21 , 22 porcine 23 and mice. 24 While recent research has highlighted the potential benefits of EGCG in safeguarding porcine oocytes from post‐ovulatory ageing by counteracting oxidative stress, 25 the comprehensive understanding of EGCG's involvement in the maturation and development of aged oocytes is still limited. Further exploration is needed to unravel the extent of EGCG's impact on aged oocytes and the underlying mechanisms that drive its effects in enhancing their maturation and developmental quality.…”

Alpha-lipoic acid attenuates heat stress-induced apoptosis via upregulating the heat shock response in porcine parthenotes

“…To determine GSH levels, blastocysts were cultured for 30 min at 38.5 °C in PBS/PVA containing 10 μM 4-chloromethyl-6,8-difluoro-7-hydroxycoumarin dye (CellTracker™ Blue CMF 2 HC, Thermo Fisher Scientific, Waltham, USA) as previously described 43 . To determine total ROS levels, blastocysts were incubated for 30 min at 38.5 °C in PBS/PVA containing 10 μM 2′,7′-dichlorodihydrofluorescein diacetate (H 2 DCF-DA, Cat # D399, Molecular Probes, Eugene, OR, USA).…”

“…As previously reported 43 , 80 porcine embryos from each group were collected in sodium dodecyl sulfate sample buffer and heated at 95 °C for 5 min. Proteins were separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and electrotransferred to polyvinylidene fluoride membranes.…”

GRP78 acts as a cAMP/PKA signaling modulator through the MC4R pathway in porcine embryonic development

“…Mitochondrial DNA copy number was measured using methods previously reported in the literature. 26 Briefly, each four blastocysts were transferred to a 0.2 mL tube containing 8 μL lysis buffer (20 mmol/L Tris, 0.4 mg/mL proteinase K, 0.9% (v/v) Nonidet-40, and 0.9% (v/v) Tween 20) and incubated at 65°C for 30 min, followed by 95°C for 5 min. Samples were diluted 1:25 in H 2 O before analysis.…”