Antioxidants

Background: Prostacyclin (PGI₂), an abundantly produced bioactive lipid by oviductal epithelial cells, supports preimplantation embryo development by buffering oxidative stress. However, the mechanism linking PGI₂ signaling to embryonic redox control remains unclear. We investigated whether Iloprost (Ilo), a stable PGI₂ analogue, enhances preimplantation embryo development by alleviating oxidative stress via activation of the Nrf2/Keap1 pathway, and whether these effects depend on Nrf2 activity using the inhibitor brusatol. Methods: Porcine embryos were treated with Ilo to model oviductal PGI₂ signaling during in vitro culture. Developmental competence was evaluated by cleavage and blastocyst formation rates, and blastocyst quality by total cell number and TUNEL assays. Oxidative status was quantified by fluorescence detection of reactive oxygen species (ROS), and Nrf2 activation was assessed by nuclear localization and antioxidant-related gene expression. Results: Embryos treated with Ilo showed significantly increased blastocyst formation, reduced ROS, and upregulated antioxidant genes. Immunofluorescence confirmed increased nuclear translocation of Nrf2, indicating activation of the Nrf2/Keap1 signaling pathway. In contrast, embryos treated with brusatol showed reduced blastocyst formation, increased ROS, and downregulated antioxidant-related gene expression, whereas co-treatment with Ilo reversed these effects. Conclusions: This study demonstrates that PGI₂ protects embryos by activating Nrf2/Keap1 signaling, establishing this axis as a key antioxidant defense during embryonic development and highlighting its potential to improve embryo culture systems.

Glucagon-like peptide-1 receptor agonists and lifestyle interventions effectively treat overt obesity, but the benefits/risks of their combined early intervention during middle age remain unclear. This study investigated whether submaximal-dose liraglutide combined with strength–endurance training improves metabolic and liver health, focusing on hepatic oxidative stress and lipid metabolism. Male Wistar rats (16 months old) received liraglutide (L; 0.186 mg/kg/day, s.c.), training (ladder climbing with weights, 3 times/week), both (L+E) or saline for control middle-aged (C) and young adults (CY; 3–4 months old) for 7 weeks (n = 8/group). Middle-aged rats exhibited age-related changes including higher body and visceral fat, increased hepatic and serum cholesterol, hepatic ALT and glutathione imbalance, and decreased soleus muscle (p < 0.05, vs. CY). Exercise increased hepatic glycogen and oxidative stress markers and downregulated lipogenic genes, consistent with liver adaptation to training. L+E synergistically reduced body and visceral fat, hepatic and serum triglycerides, and the triglyceride–glucose index, while reducing oxidative stress (p < 0.05 vs. E, C) and lipogenic gene expression (p < 0.05 vs. C), without affecting pancreas histopathology and function parameters, muscle mass or exercise load volume. In conclusion, submaximal liraglutide safely synergized with training to enhance metabolic health, improve hepatic redox balance and triglyceride metabolism in middle-aged rats, without mitigating cholesterol rise.

Background: Aging elevates reactive oxygen species (ROS) and weakens antioxidant defenses, contributing to cardiac dysfunction. The objective of this study was to determine whether sustained activation of skeletal muscle (SkM) Nrf2 preserves cardiac function during aging and to explore the underlying mechanisms, focusing on myocardial antioxidant pathways. Methods: Tamoxifen-induced SkM-specific Keap1 knockout male mice (iMS-Keap1^flox/flox; SkM-Nrf2 overexpression) were divided into young wild-type (Y-WT), aged wild-type (A-WT), and aged knockout (A-KO) groups. Cardiac performance was evaluated by echocardiography and invasive hemodynamics. Myocardial proteomics identified differentially expressed proteins (DEPs) and enriched biological pathways. Results: Compared with Y-WT, A-WT mice showed impaired left ventricular function, including reduced ejection fraction, prolonged isovolumic relaxation time, blunted inotropic response to dobutamine, and elevated Tau index. These age-related deficits were partially reversed in A-KO mice. Proteomic analysis revealed 561 DEPs between A-WT and Y-WT, and 741 DEPs between A-KO and A-WT, enriched in calcium signaling, Nrf2-mediated oxidative stress response, oxidative phosphorylation, ROS detoxification, and cardiac-specific processes, such as hypertrophy, conduction, and dilated cardiomyopathy. Conclusions: Lifelong SkM-Nrf2 activation strengthens myocardial antioxidant capacity and alleviates age-related cardiac dysfunction. These data support an antioxidant crosstalk between skeletal muscle and the heart, highlighting a potential therapeutic target for aging-associated heart failure.