Urolithin A, which is a natural gut microbial metabolite, exerts multiple beneficial effects upon supplementation, including prolonging lifespan, mitigating diseases, restoring the quality of aged oocytes and alleviating drug toxicity. The study aims to investigate the ovarian protective role of Urolithin A using a neonatal mouse ovarian in vitro culture and chemotherapy model, with a particular focus on its mechanisms for inhibiting primordial follicle activation and mitigating cyclophosphamide (CY) or 4-hydroperoxy (4-HC)-induced follicle apoptosis. The results showed that Urolithin A significantly decreased the number of growing follicles and downregulated the expression of oocyte growth-related genes (Gdf9 and Zp3) and protein (DDX4), as well as Ki-67 and BrdU-positive signals. Further studies revealed that Urolithin A significantly downregulated the levels of phosphorylated Akt and FOXO3a and decreased the percentage of oocytes with FOXO3a nuclear export. Molecular docking showed a strong binding ability between Urolithin A and its downregulated gene Pik3cg. Moreover, Urolithin A significantly decreased CY- and 4-HC-induced increases in cleaved Caspase-3- and PARP1-positive signals. Meanwhile, RNA-seq analysis indicated that Urolithin A significantly downregulated CY-induced expression of DNA damage-related genes (Trp73 and Trim29). In short, Urolithin A inhibits primordial follicle activation by reducing PI3K/Akt signaling reactivity. Furthermore, Urolithin A prevents CY-induced follicle apoptosis. The study provides valuable insights into Urolithin A treatment for chemotherapy-induced infertility.

Methionine serves as an essential amino acid regulating de novo protein synthesis and redox homeostasis. Previous studies have established adverse impacts of methionine restriction and deprivation on semen quality, but effects on early spermatogenesis remain poorly characterized. In this study, a methionine dietary model (0.86%, 0.17%, 0%) was used to investigate the role of methionine in early spermatogenesis. The results indicated that methionine deprivation caused spermatogenesis defects by inhibiting spermatogonial proliferation and increasing apoptosis. Further studies showed that methionine deprivation downregulated mitochondrial function-related genes ( Gpx4 , Fis1 and Gstm1 ), but upregulated ISR- ( Atf4 , Chac1 and Ddit3 ) and DNA damage response-related genes ( Cdkn1a , Chek2 and Atm ). Meanwhile, methionine deprivation caused mitochondrial dysfunction characterized by mitochondrial membrane potential depolarization, ROS accumulation, and MitoSOX accumulation. Methionine deprivation also caused an obvious increase in DNA damage response proteins (γH2AX, p-CHK2 and p-p53) and pro-apoptotic proteins (PUMA, BAX and c-PARP1), but suppressed anti-apoptotic protein BCL2. Furthermore, NAC effectively reversed the proliferation deficiency of GC-1 cells caused by methionine deprivation. Collectively, these findings suggest that methionine deprivation triggers ISR activation, which subsequently induces spermatogonial apoptosis via oxidative stress and the CHK2-p53/p21 signaling cascade. This study highlights the critical role of methionine in early spermatogenesis, provides mechanistic insights for optimizing dietary interventions and addresses related reproductive disorders.

Background: Sperm quality plays an important role in the animal industry. The study of the sperm quality of Congjiang Xiang pigs is limited and the Rh123/PI double staining has not been used to detect the sperm quality of boars. Thus, the study aimed to evaluate the sperm quality of the Congjiang Xiang pigs and the feasibility of the flow cytometry (FCM) method in assessing sperm quality in pigs. Methods: Semen samples were evaluated for routine indicators of semen quality and using FCM with single staining and double staining to analyze the integrity of membrane and acrosome, the mitochondrial function. The sperm quality of the Congjiang Xiang pigs was compared with the Large White pigs. Result: The semen of the Congjiang Xiang pigs had a lower sperm concentration than that of the Large White pigs (P less than 0.01). There were no significant differences in sperm vitality, sperm motility and abnormality between the two breeds (P greater than 0.05). Single sperm staining revealed a lower sperm acrosomal integrity in the semen of the Congjiang Xiang pigs than that of the Large White pigs (P less than 0.01). No significant difference between the two breeds in membrane integrity and mitochondrial function was observed (P greater than 0.05). Rh123/PI double staining demonstrated that the rate of live sperm with a normal mitochondrial function of the Congjiang Xiang pigs was significantly higher than that of the Large White pigs (P less than 0.05). The rate of necrotic sperms in the semen of the Congjiang Xiang pigs was significantly lower than that in the semen of the Large White pigs (P less than 0.05). Correlation analysis revealed a positive association between the rates of live sperm in the semen of the congjiang xiang pigs and their sperm motility (P=0.051). Our results suggest that Rh123/PI double staining with flow cytometry can provide more reliable information to assess the boar sperm quality.