Both the livestock and biomedical fields require a large supply of high-quality mature oocytes. However, the in vitro maturation (IVM) process often leads to an accumulation of reactive oxygen species (ROS), which can cause defects in oocyte meiosis and embryo development, ultimately compromising oocyte quality. Urolithin A (UA), known for its antioxidant properties, has not been thoroughly investigated for its potential to mitigate the negative effects of oxidative stress during the in vitro culturing of oocytes, and its underlying mechanism is not well understood. In this study, an in vitro oxidative stress model was established using porcine oocytes treated with H₂O₂, followed by exposure to varying concentrations of UA. The results revealed that 30 μM UA significantly improved both the quality of oocyte culture and the developmental potential of the resulting embryos. UA was found to enhance oocyte autophagy, reduce oxidative stress-induced mitochondrial damage, and restore mitochondrial function. Additionally, it lowered ROS and DNA damage levels in the oocytes, maintained proper spindle/chromosome alignment and actin cytoskeleton structure, promoted nuclear maturation, prevented abnormal cortical granule distribution, and supported oocyte cytoplasmic maturation. As a result, UA alleviated oxidative stress-induced defects in oocyte maturation and cumulus cell expansion, thereby improving the developmental potential and quality of parthenogenetic embryos. After supplementation with UA, pig parthenogenetic embryo pluripotency-related genes (Nanog and Sox2) and antiapoptotic genes (Bcl2) were upregulated, while proapoptotic genes (Bax) were downregulated. In conclusion, this study suggests that adding UA during IVM can effectively mitigate the adverse effects of oxidative stress on porcine oocytes, presenting a promising strategy for enhancing their developmental potential in vitro.

Semen cryopreservation is associated with sperm vulnerability to oxidative stress and ice crystal-induced damage, adversely affecting in vitro fertilization (IVF) success. This study aimed to investigate the effects of freezing diluent supplemented with antioxidant limonin (Lim), myo-inositol (MYO), and the ice crystal formation inhibitor L-proline (LP) through sperm motility, morphological integrity, and antioxidant capacity. The Lim (150 mM), MYO (90 mM), and LP (100 mM) significantly ameliorated the quality of post-thaw sperm in Debao boar, and combined treatment of these agents significantly enhanced sperm motility, structural integrity, and antioxidant capacity compared with individual agents (p < 0.05). Notably, the combined use of these agents reduced glycerol concentration in the freezing diluent from 3% to 2%. Meanwhile, the integrity of the sperm plasma membrane, acrosome membrane, and mitochondrial membrane potential was significantly improved (p < 0.05), and the result of IVF revealed the total cell count of the blastocysts was also greater in the 2% glycerol group (p < 0.05). In conclusion, the newly developed freezing diluent for semen, by adding Lim (150 mM), MYO (90 mM), and LP (100 mM), can enhance the quality of frozen–thawed Debao boar sperm and reduce the concentration of glycerol from 3% to 2% as high concentrations of glycerol can impair the quality of thawed sperm and affect in vitro fertilization outcomes. In conclusion, the improved dilution solution formulated demonstrated efficacy in enhancing the quality of porcine spermatozoa following cryopreservation and subsequent thawing.

The specific expression profile and function of circular RNA (circRNA) in follicular atresia remain largely unknown. Here, the circRNA expression profiles of granulosa cells derived from healthy follicles (HFs) and antral follicles (AFs) in buffalo were analyzed by RNA-seq, and the mechanism of a differentially expressed circRNA (DEcircRNA) circTEC regulating the granulosa cell function that affects follicular atresia was further explored. RNA-seq results showed that a total of 112 DEcircRNAs were identified. Among them, circTEC was highly expressed in HF, and its circular structure was confirmed by RNase R digestion assay, reversed PCR and Sanger sequencing. Functional experiments demonstrated that circTEC promotes the proliferation and steroid hormone synthesis of buffalo granulosa cells (bGCs), and it also inhibits their apoptosis. In-depth mechanism analysis showed that the expression level of circTEC in bGCs from AFs was adversely related to miR-144-5p and consistent with FZD3. CircTEC acts as an endogenous sponge of miR-144-5p to regulate the expression of the target gene FZD3 in AFs, which promotes the proliferation of bGCs and inhibits bGCs apoptosis, thereby inhibiting follicular atresia in buffalo. In summary, our study revealed the regulatory role of the circTEC/miR-144-5p/FZD3 axis during follicular atresia in buffalo. These results provided new insights into the biological mechanism underlying follicular atresia.

The river buffalo is an economically important livestock species supplying milk and meat. However, a multi-tissue transcriptomic atlas for the key dairy river buffalo breeds, Murrah and Nili-Ravi, has not yet been established, and the lack of stable reference genes has hindered in-depth studies of their biological functions and the molecular mechanisms underlying key economic traits such as lactation. We established a multi-tissue gene expression atlas across 20 tissues and identified 717 housekeeping genes (HKGs), and RPL37A and EEF2 were further shown to be stable candidate reference genes under the conditions tested. We found 8368 tissue-specific genes (TSGs), predominantly enriched in the reproductive system. Exploratory analysis of mammary tissue (dry-period vs. public lactating samples, confounded by batch effects) revealed mammary-enriched hub genes including LALBA; these findings are preliminary and require validation. Dynamic analysis across lactation stages (early, peak, mid-, late) identified candidate genes including SEC14L2 and ACSM3. Phenotypic data showed strong negative correlations between milk yield and protein/fat content, and a positive correlation with lactose content. However, causal or regulatory roles were not inferred due to lack of paired individual-level data. Cross-dataset comparisons are descriptive only, and are not key conclusions. In summary, this study lays the foundation for advancing research in lactation trait genetics and functional genomics in river buffalo, with novel reference genes and lactation stage-specific transcriptional dynamics as its main contributions.