Decrease In Follicles Research Articles

Ti3C2 nanosheet-induced autophagy derails ovarian functions

BackgroundTwo-dimensional ultrathin Ti3C2 (MXene) nanosheets have gained significant attention in various biomedical applications. Although previous studies have described the accumulation and associated damage of Ti3C2 nanosheets in the testes and placenta. However, it is currently unclear whether Ti3C2 nanosheets can be translocated to the ovaries and cause ovarian damage, thereby impairing ovarian functions.ResultsWe established a mouse model with different doses (1.25, 2.5, and 5 mg/kg bw/d) of Ti3C2 nanosheets injected intravenously for three days. We demonstrated that Ti3C2 nanosheets can enter the ovaries and were internalized by granulosa cells, leading to a decrease in the number of primary, secondary and antral follicles. Furthermore, the decrease in follicles is closely associated with higher levels of FSH and LH, as well as increased level of E2 and P4, and decreased level of T in mouse ovary. In further studies, we found that exposure toTi3C2 nanosheets increased the levels of Beclin1, ATG5, and the ratio of LC3II/Ι, leading to autophagy activation. Additionally, the level of P62 increased, resulting in autophagic flux blockade. Ti3C2 nanosheets can activate autophagy through the PI3K/AKT/mTOR signaling pathway, with oxidative stress playing an important role in this process. Therefore, we chose the ovarian granulosa cell line (KGN cells) for in vitro validation of the impact of autophagy on the hormone secretion capability. The inhibition of autophagy initiation by 3-Methyladenine (3-MA) promoted smooth autophagic flow, thereby partially reduced the secretion of estradiol and progesterone by KGN cells; Whereas blocking autophagic flux by Rapamycin (RAPA) further exacerbated the secretion of estradiol and progesterone in cells.ConclusionTi3C2 nanosheet-induced increased secretion of hormones in the ovary is mediated through the activation of autophagy and impairment of autophagic flux, which disrupts normal follicular development. These results imply that autophagy dysfunction may be one of the underlying mechanisms of Ti3C2-induced damage to ovarian granulosa cells. Our findings further reveal the mechanism of female reproductive toxicity induced by Ti3C2 nanosheets.

The Role of Physical Activity in Menopausal Women

Menopause is the permanent cessation of the menstrual cycle due to decreased ovarian function, resulting in a decrease in follicles. A person is said to be experiencing menopause if they do not experience menstruation for 12 months. Symptoms that occur during menopause include somatic, psychological, and urogenital symptoms. Exercise has many benefits for body health. Exercise, such as regular physical activity, is considered to reduce complaints during menopause. This study aims to identify the relationship between various physical activities and menopausal symptoms in women aged 50-60 years in the working area of the Ujunggading Health Center. This research uses a correlation research design with a cross-sectional approach model with a sample size of 75 respondents using the nonprobability sampling method, namely using purposive sampling, data collection using GPAQ and MRS questionnaires, and data analysis using correlation tests. The results of the research from 75 respondents showed that the frequency distribution of the characteristics of respondents with the highest occupation was as a housewife, namely 23 people (30.7%), the highest education was junior high school, namely 20 people (26.7%), and the highest duration of menopause was 5-7 years, namely 36 people (48.0%). Shows that many respondents have physical activity in the moderate category 54 (72%), and many respondents experience menopausal symptoms in the moderate category 37 (49.3%). There is a relationship between physical activity and menopausal symptoms with a p-value = 0.000 (p<0.05). There is a relationship between physical activity and menopausal symptoms where the higher the physical activity carried out, the less menopausal symptoms are felt, menopausal symptoms can be reduced by routinely doing activities and exercising for 15 to 60 minutes every day.

Morphological study of isolated ovarian preantral follicles using fibrin gel plus platelet lysate after subcutaneous transplantation.

Ovarian and follicle transplantation may preserve fertility in young cancer survivors. In this study, we have transplanted preantral follicles using fibrin gel as a carrier and fibrin gel supplemented with platelet lysate (PL) as a rich source of angiogenic and growth factors. The purpose of this study was to evaluate the role of fibrin gel and PL in follicle transplantation. In this experimental study, ovaries were taken from 14-day- old Naval Medical Research Institute (NMRI) mice. Preantral follicles were dissected from the ovaries and encapsulated into fibrin gel supplemented with 5, 10, 15 or 20% PL, then transplanted back into the same donor mice. Fibrin gels supplemented with PL that contained preantral follicles were placed in a subcutaneous pocket in the back of the neck of the recipient, donor mouse (the same mouse that follicles were collected). After 14 days the grafts were processed and embedded in paraffin blocks, then serially sectioned for histological evaluation. We counted the follicles and classified them according to stage (preantral or antral). Data were presented as mean ± standard error of mean (SEM) and analysed by analysis of variance (ANOVA) and the Kruskal-Wallistest. The mean percentage of recovered follicles encapsulated and transplanted in each group were 33.30 ± 2.47 (fibrin gel), 31.96 ± 1.90 (fibrin gel+5% PL), 34.02 ± 2.44 (fibrin gel+10% PL), 48.31 ± 2.06 (fibrin gel+15% PL) and 17.60 ± 2.79 (fibrin gel+20% PL). There was a significant increase in the recovery rate of grafted follicles with fibrin gel+15% PL (48.31%; p<0.001). The percentage of preantral follicles showed no significant difference in all groups (p<0.05). The percentage of antral follicles showed a significant decrease in follicles grafted with fibrin gel+20% PL when compared to the other groups (11.77%; p<0.005) but no significant difference was observed in the other groups. The use of PL in follicle transplantation can improve ovarian follicular survival rate.

Collaborative work on evaluation of ovarian toxicity by repeated-dose and fertility studies in female rats

The National Institute of Health Sciences (NIHS) and 18 pharmaceutical companies of the Japan Pharmaceutical Manufacturers Association (JPMA) have conducted a validation study intended to evaluate whether a 2-week repeated general toxicity period with histopathological examination is sufficient to detect ovarian toxicity or not. The current repeated dose general toxicity study is considered to be insufficient in terms of evaluating female reproductive function due to a lack of evidence indicating that it is adequate. Evaluation of ovarian toxicity by comprehensive histopathological examination of the female reproductive organs based on the underlying morphology of a normal cycle of the reproductive tract including the ovary and additional immunohistochemical staining with proliferative cell nuclear antigen (PCNA) to identify small follicles may be a good tool to assess female reproductive function. In the collaborative study, 2- or 4-week repeated dose toxicity studies with ovarian histopathological examinations were conducted. A female fertility study was also conducted to compare the results with those of the ovarian histopathological findings. A total of 17 test substances were evaluated and categorized into hormone analogues, primordial follicle damaging agents, metabolite imbalance inducers, and endocrine imbalance inducers. Based on the results, ovarian toxicity could be detected by a careful histopatholgical examination. A 2-week dosing period may be sufficient for the evaluation of ovarian toxicity, except for cytotoxic compounds such as alkylating agents. The pathological findings of ovarian toxicity (decreases in follicles, increases in atretic follicles, increases in currently formed corpora lutea, etc) reflected the female fertility parameters (irregular estrous cycle, pre-implantation loss).

Fate of the initial follicle pool: Empirical and mathematical evidence supporting its sufficiency for adult fertility

The importance of the initial follicle pool in fertility in female adult mammals has recently been debated. Utilizing a mathematical model of the dynamics of follicle progression (primordial to primary to secondary), we examined whether the initial follicle pool is sufficient for adult fertility through reproductive senescence in CD1 mice. Follicles in each stage were counted from postnatal day 6 through 12 months and data were fit to a series of first-order differential equations representing two mechanisms: an initial pool of primordial follicles as the only follicle source (fixed pool model), or an initial primordial follicle pool supplemented by germline stem cells (stem cell model). The fixed pool model fit the experimental data, accurately representing the maximum observed primary follicle number reached by 4–6 months of age. Although no germline stem cells could be identified by SSEA-1 immunostaining, the stem cell model was tested using a range of de novo primordial follicle production rates. The stem cell model failed to describe the observed decreases in follicles over time and did not parallel the accumulation and subsequent reduction in primary follicles during the early fertile lifespan of the mouse. Our results agree with established dogma that the initial endowment of ovarian follicles is not supplemented by an appreciable number of stem cells; rather, it is sufficient to ensure the fertility needs of the adult mouse.

Postnatal Changes in Mice Exposed In Utero to Fast Neutrons

Exposure to radiation during brain development stage cause microcephaly or mental retardation. Although X- and gamma-rays induced cerebral hypoplasia in rodents has been well characterized, little is known about such effects of neutrons. To examine the effects of prenatal exposure to neutrons on the development of brain and other organs, both male and female B6C3F1 mice were irradiated with fast neutrons (0.1, 0.2, 0.5, 1 Gy) or gamma-rays (0.8, 1.5 Gy) at embryonic day 13.5, and the animals were examined histopathologically 56 days after birth. Both types of radiation mainly caused hypoplasia of the cerebral cortex and lowered brain absolute weight. No sex differences were seen. These changes were remarkable in each highest dose group. The weight loss of the brain was noted at the lowest dose group of neutrons. In addition, the weight loss of the thymus, atrophy of the seminiferous tubules, and a decrease in follicles of the ovary were also noted in the higher dose groups of neutrons and gamma-rays. The degrees of these changes were larger for neutrons.

A repeated 28-day oral dose toxicity study of methoxychlor in rats, based on the 'enhanced OECD test guideline 407' for screening endocrine-disrupting chemicals.

In association with the international validation project to establish an OECD Enhanced Test Guideline 407, we performed a 28-day repeated-dose toxicity study of methoxychlor, a chlorinated hydrocarbon pesticide with pro-estrogenic and anti-androgenic activities. Attention was paid to the sensitivity of certain additional parameters for detecting endocrine related effects of endocrine disrupting chemicals based on the existing TG 407. Seven-week-old Crj:CD(SD)IGS rats were allocated to one of four groups, each consisting often males and ten females, and methoxychlor was administered once daily by gavage at doses of 0 (control), 20, 100 or 500 mg/kg body weight per day. Male rats were killed on the day after the 28th administration. Female rats were killed on the day of the diestrus stage during 4 days after the 28th administration. Male rats receiving methoxychlor showed mainly atrophy of mammary acinus in the 20 mg/ kg and higher groups, together with decreases in prostate and seminal vesicle weights, and atrophy of epididymis, prostate, seminal vesicle and coagulating gland in the 100 and 500 mg/kg groups. In addition, decrease in serum testosterone level, increase in follicle-stimulating hormone level, decrease in testis and epididymis weights, atrophy of semiferous tubules and Leydig cells, decrease in the number of sperm in the caudal epididymis and their motility were observed in the 500 mg/kg group. Female rats receiving methoxychlor showed mainly abnormal estrous cycles, decrease in serum luteinizing hormone level, decrease in ovary weight, proliferation of mammary acinus, atrophy of ovary due to decrease in follicles and corpus luteum in histopathology, hypertrophy of endometrial epithelium of uterus and vagina epithelium in the 100 and 500 mg/kg groups. Among the parameters tested in the present experimental system, effects of methoxychlor on endocrine-related organs were detected with regard to serum hormone, organ weights, histopathological examination in both sexes, estrus cycle in females and sperm examination in males. Based on these results, a no-observed-adverse-effect level (NOAEL) in the present study was estimated to be below 20 mg/kg per day. In particular, the adverse effects were effectively detected in organ weights of accessory sex organs and histopathological examination.

Shift in Steroidogenesis in the Ovarian Follicles of the Goldfish (Carassius auratus) during Gonadotropin-Induced Oocyte Maturation: (oocyte maturation/gonadotropin/steroidogenesis/ovarian follicle/goldfish).

Both partially purified chum salmon gonadotropin and 17α-hydroxyprogesterone stimulated in vitro production of testosterone by postvitellogenic follicles of goldfish (Carassius auratus). Chum salmon gonadotropin further enhanced the conversion of exogenously supplied 17α-hydroxyprogesterone to 17α, 20β-dihydroxy-4-pregnen-3-one. The increased medium concentrations of 17α, 20β-dihydroxy-4-pregnen-3-one were associated with the induction of final oocyte maturation. The capacity of postvitellogenic follicles to produce steroids in response to exogenous 17α-hydroxyprogesterone was examined in females at various stages of final oocyte maturation following the administration of human chorionic gonadotropin in vivo combined with elevation of holding temperature. The maximum production of testosterone in response to 17α-hydroxyprogesterone was obtained in follicles from initial controls. In contrast, 17α 20β-diOHprog production was very low in initial controls and markedly increased during oocyte maturation (3-6 hr following injection), followed by a significant decrease in follicles collected at 15 hr. Estradiol-17β production by the follicles was very low at any stages of gonadotropin-induced oocyte maturation. These results suggest that gonadotropin-induced shift in the biosynthetic pathway in the follicle from the secretion of predominantly testosterone to 17α, 20β-dihydroxy-4-pregnen-3-one secretion is a prerequisite step for the induction of oocyte maturation in goldfish.