Search

Introduction: Ovarian aging is characterized by a gradual decline in quantity and quality of oocytes and lower chance of fertility. Better understanding the genetic modulation during ovarian aging can further address available treatment options for aging-related ovarian diseases and fertility preservation. Methods: A novel technique spatial transcriptomics (ST) was used to investigate the spatial transcriptome features of rat ovaries. Transcriptomes from ST spots in the young and aged ovaries were clustered using differentially expressed genes. These data were analyzed to determine the spatial organization of age-induced heterogeneity and potential mechanisms underlying ovarian aging. Results: In this study, ST technology was applied to profile the comprehensive spatial imaging in young and aged rat ovary. Fifteen ovarian cell clusters with distinct gene-expression signatures were identified. The gene expression dynamics of granulosa cell clusters revealed three sub-types with sequential developmental stages. Aged ovary showed a significant decrease in the number of granulosa cells from the antral follicle. Besides, a remarkable rearrangement of interstitial gland cells was detected in aging ovary. Further analysis of aging-associated transcriptional changes revealed that the disturbance of oxidative pathway was a crucial factor in ovarian aging. Conclusions: This study firstly described an aging-related spatial transcriptome changes in ovary and identified the potential targets for prevention of ovarian aging. These data may provide the basis for further investigations of the diagnosis and treatment of aging-related ovarian disorders. [ABSTRACT FROM AUTHOR]

There is evidence of an association between exposure to ambient fine particulate matter (PM2.5) and female ovarian dysfunction in adults. However, it is not fully clear whether maternal exposure to PM2.5 negatively affects the ovarian function in offspring. The size of primordial follicle pool, definitely assembled during fetal life, determines ovarian reserve and ovarian function. In this study, female C57BL/6 mice were exposed to either ambient PM2.5 (mean daily concentration 49 µg/m3) or filtered air through a whole-body exposure system for 4 weeks before mating, and remained exposed until postpartum. We found that maternal exposure to PM2.5 reduces the initial size of primordial follicle pool and impairs its development in offspring mice. The number of primordial follicles and total follicles was decreased in PM2.5-exposed offspring mice on postnatal day 3 (PND3) and postnatal day 7 (PND7). Maternal PM2.5 exposure promoted the activation of primordial follicles and upregulated the level of p-AKT in offspring mice, accelerating the depletion of primordial follicle pool. While LY294002, a specific inhibitor of PI3K, reversed the overactivation of primordial follicles induced by PM2.5. Besides, maternal PM2.5 exposure induced follicular atresia and granulosa cell apoptosis, increased the accumulation of lipid peroxidation products 4-HNE, and elevated the expression of oxidative stress-related genes and p-p65, p-IκBα in offspring mice. While N-acetylcysteine (NAC) pretreatment abolished the increases of apoptosis, reactive oxygen species (ROS), p-p65 and p-IκBα levels in ovarian granulosa COV434 cells induced by PM2.5 exposure. These findings reveal that maternal exposure to PM2.5 decreases the initial size of primordial follicle pool, and impairs ovarian follicular development in offspring mice. Our data suggest that this involves the activation of the PI3K/AKT/FoxO3a pathway and the ROS-dependent NF-κB pathway. Our study implicates a link between maternal PM2.5 exposure and ovarian reserve in offspring, and improves our understanding of the effects of PM2.5 on reproductive health. [Display omitted] • Maternal PM2.5 exposure reduces ovarian reserve. • Maternal PM2.5 exposure accelerates primordial follicle activation through the PI3K/AKT/FoxO3a pathway. • Maternal PM2.5 exposure induces follicular atresia through ROS-dependent NF-κB pathway. [ABSTRACT FROM AUTHOR]