Fetal exposure of Aristolochic Acid I undermines ovarian reserve by disturbing primordial folliculogenesis.

The primordial follicle pool established in early life determines the ovarian reserve in the female reproductive lifespan. Premature exhaustion of primordial follicles contributes to primary ovarian insufficiency (POI), that is dependent by the initial size of the primordial follicle pool and by the rate of its activation and depletion. AAI, a powerful nephrotoxin with carcinogenic potential, is present in the Aristolochiaceae species, which can release AAI into soil as a persistent pollutant. In order to assess the potential risk of Aristolochic Acid I (AAI) exposure on mammalian oogenesis, we uncovered its adverse effect on primordial folliculogenesis in the neonatal mouse ovary and its effect on female fertility in adulthood. Pregnant mice were orally administrated with doses of AAI without hepatic or renal toxicity during late-gestation. Ovaries from offspring of administered female displayed gross aberrations during primordial folliculogenesis. Also, unenclosed oocytes in germ-cell cysts showed increased DNA damage. Furthermore, several key factors, including NANOS3, SOX9, KLF4, that govern early gonad's differentiation were abnormally expressed in the exposed ovary, while the follicle formation was partially restored by knockdown of Nanos3 or sox9. In adulthood, these aberrations evolved into a significant reduction in offspring number and impaired ovarian reserve. Together, our results show that AAI influences primordial folliculogenesis and, importantly, affected female fertility. This study shows that administration of drugs herbs or consumption of vegetables that contain AAs during pregnancy may adversely influence the fertility of offspring.

Application of new evaluation system based on virtual simulation system in experimental teaching of functional science / 中华医学教育探索杂志

Objective:To explore the application effect of a new evaluation system based on virtual simulation system in the evaluation of functional science experiment teaching.Methods:The data of students' learning in the 2019-2020 academic year were collected, and the impact of using virtual simulation teaching system on the achievement of teaching goals under the new teaching evaluation standard was comparatively analyzed. Questionnaire survey was conducted to study students' evaluation on the virtual simulation teaching system. SPSS 22.0 was used for chi-square test.Results:The students who used the new formative evaluation standard had a virtual academic excellence rate of 75.49% (308/408), while the unused students had an excellence rate of only 32.22% (135/419), with significant differences ( P<0.01). The number of virtual simulation items required for different teaching objectives were 4, 11 and 14, respectively, and the corresponding students' virtual simulation system outstanding rate was 99.19% (246/248), 93.14% (380/408), 84.72% (488/576), with significant differences ( P<0.01). And 93.8% (348/371) students thought the learning of the virtual simulation system could help improve the success rate of the experiment, and 93.26% (346/371) of the students believed that it had improved the ability to analyze and deal with unexpected problems in the experimental class. Conclusion:The new evaluation system based on the virtual simulation system can promote the improvement of the experimental teaching quality of functional science.

Autophagy participates in cyst breakdown and primordial folliculogenesis by reducing reactive oxygen species levels in perinatal mouse ovaries.

The reserve of primordial follicles, which serves all oocytes for the female reproductive lifespan, is established a few days after birth in mice. During this process, more than half of the oocytes are primarily eliminated by apoptosis. Autophagy, the conserved intracellular process maintaining cellular homeostasis, serves as a protective mechanism for oocyte survival. In the current study, we speculate a new role for autophagy during primordial folliculogenesis. Active autophagy was observed in perinatal ovaries from 16.5 days post coitus to 3 days post parturition. The inhibition of autophagy by 3-methyladenine (3-MA) increased the number of cyst oocytes and delayed follicle formation in vivo and in organ cultures. Furthermore, the reactive oxygen species (ROS) level was elevated in ovaries treated with 3-MA, while N-acetylcysteine, an oxidant, alleviated the inhibitory effect of 3-MA on primordial folliculogenesis. Additionally, the expression of growth differentiation factor 9 and transforming growth factor ß1, which regulates follicle activation, was decreased after 3-MA treatment. These data suggest that the physiological level of autophagy in perinatal ovaries regulates germ cell cyst breakdown and primordial follicle assembly by ROS clearance and exerts extensive effects on further follicular development.