Fetal programming: in utero exposure to acrylamide leads to intergenerational disrupted ovarian function and accelerated ovarian aging

In this study we investigated the effects of multigenerational exposures to acrylamide (ACR) on ovarian function. Fifty-day-old Wistar albino female rats were divided into the control and ACR-treated groups (2.5, 10, and 20 mg/kg/day) from day 6 of pregnancy until delivery. The obtained females of the first (AF1) and second generation (AF2) were euthanized at 4 weeks of age, and plasma and ovary samples were collected. We found that in utero multigenerational exposure to ACR reduced fertility and ovarian function in AF1 through inducing histopathological changes as evidenced by the appearance of cysts and degenerating follicles, oocyte vacuolization, and pyknosis in granulosa cells. TMR red positive cells confirmed by TUNEL assay were mostly detected in the stroma of the treated groups. Estradiol and IGF-1 concentrations significantly decreased as a result of decreased CYP19 gene and its protein expression. However, ACR exposure in AF2 led to early ovarian aging as evidenced by high estradiol and progesterone levels among all treated groups compared to control group, corresponding to the upregulation of the CYP19 gene and protein expression. The apoptotic cells of the stroma were greatly detected compared to that in the control group, whereas no significant difference was reported in ESR1 and ESR2 gene expression. This study confirms the developmental adverse effects of ACR on ovarian function and fertility in at least two consecutive generations. It emphasizes the need for more effective strategies during pregnancy, such as eating healthy foods and avoiding consumption of ACR-rich products, including fried foods and coffee.

Secoisolariciresinol Diglucoside Improves Ovarian Reserve in Aging Mouse by Inhibiting Oxidative Stress

Ovarian reserve is a key factor in the reproductive function of the ovaries. Ovarian aging is characterized by a gradual decline in the quantity and quality of follicles. The underlying mechanism of ovarian aging is complex and age-related oxidative stress is considered one of the most likely factors. Secoisolariciresinol diglucoside (SDG) has been shown to have good scavenging ability against reactive oxygen species (ROS) which slowly accumulates in ovarian tissues. However, it is unknown whether SDG had beneficial effects on aging ovaries. In this study, we used 37-week-old female C57BL/6J mouse as a natural reproductive aging model to evaluate the role of SDG in ovarian aging. SDG (7 and 70 mg/kg) intragastric administration was performed in the mice daily. After 8 weeks, the effects of SDG on aging ovaries were evaluated by counting the number of follicles and the expression of follicle-stimulating hormone receptors (FSHR) in the ovary. The mechanism of SDG on the aging ovaries was further explored through ovarian metabolomics. It was found that SDG can effectively increase the number of growing follicles and increase the expression of the FSHR protein. The metabolomics results showed that the ovaries in the SDG intervention group achieved better uptake and transport of nutrients, including amino acids and glucose that are necessary for the development of oocytes. At the same time, the ovaries of the SDG intervention group showed that the drug reduced ROS generation. Additionally, we found that ovarian telomere length and ovarian mitochondrial DNA copy number that are highly susceptible to ROS damage and are also related to aging. The results showed that SDG can significantly increase mitochondrial DNA copy number and slow down the process of telomere shortening. These data indicate that SDG improves ovarian reserve by inhibiting oxidative stress.

Advanced maternal age alters expression of maternal effect genes that are essential for human oocyte quality

To investigate the effects of maternal age on the quality of oocytes, we used single-cell RNA sequencing to detect global gene transcriptome and identify key genes affected by advanced age in human mature oocytes. We isolated mRNA from mature oocytes obtained from IVF or ICSI patients (three oocytes from younger (≤30 years) and three oocytes from older (≥40 years) patients for scRNA-seq. We identified 357 genes differentially expressed between matured oocytes from older and younger women's. The up-regulated genes were significantly enriched with annotations related to transcriptional activation, oxidative stress and immune function, while down-regulated genes were enriched with catalytic activity. The key candidate gene TOP2B was found by protein interaction network analysis, and knockdown verification on younger mouse matured oocytes showed that TOP2B was a key gene affecting the oocyte quality and early embryo development. These results will contribute new knowledge on the molecular mechanisms of female ovary aging and establish a criterion to evaluate the quality of oocytes in women with advanced maternal age.

Curcumin exerts a protective effect against premature ovarian failure in mice

This study was designed to investigate the protective effect of curcumin against d-galactose (d-gal)-induced premature ovarian failure (POF) in mice. A mouse POF model was induced by subcutaneous injection of d-gal (200 mg/kg/day) daily for 42 days. Mice in the curcumin group received both d-gal treatment and intraperitoneal injection of curcumin (100 mg/kg/day) for 42 days. Ovarian function, oxidative stress and apoptosis were evaluated. The P, E2 and SOD levels were higher, and the FSH, LH and MDA levels were significantly lower in the curcumin group than those in the d-gal group. The proportion of primordial follicles was also significantly higher in the curcumin group than that in the d-gal group. In addition, curcumin treatment after d-gal administration resulted in significantly lower Sod2, Cat, 8-OhdG, 4-HNE, NTY and senescence-associated protein P16 expression levels, higher Amh expression levels and less apoptosis in granulosa cells than was observed in the d-gal group. Moreover, the p-Akt, Nrf2 and HO-1 protein expression levels were significantly higher and the apoptosis-related cleaved caspase-3 and -9 protein expression levels were markedly lower in the curcumin group than in the d-gal group. In conclusion, curcumin effectively inhibited d-gal-induced oxidative stress, apoptosis and ovarian injury via a mechanism involving the Nrf2/HO-1 and PI3K/Akt signaling pathways, suggesting that curcumin is a potential protective agent against POF.