Exposure to environmentally relevant concentrations of ambient fine particulate matter (PM2.5) depletes the ovarian follicle reserve and causes sex-dependent cardiovascular changes in apolipoprotein E null mice

Background Fine particulate matter (PM2.5) exposure accelerates atherosclerosis and contains known ovotoxic chemicals. However, effects of exposure to PM2.5 on the finite ovarian follicle pool have hardly been investigated, nor have interactions between ovarian and cardiovascular effects. We hypothesized that subchronic inhalation exposure to human-relevant concentrations of PM2.5 results in destruction of ovarian follicles via apoptosis induction, as well as accelerated recruitment of primordial follicles into the growing pool. Further, we hypothesized that destruction of ovarian follicles enhances the adverse cardiovascular effects of PM2.5 in females. Results Hyperlipidemic apolipoprotein E (Apoe) null ovary-intact or ovariectomized female mice and testis-intact male mice were exposed to concentrated ambient PM2.5 or filtered air for 12 weeks, 5 days/week for 4 h/day using a versatile aerosol concentration enrichment system. Primordial, primary, and secondary ovarian follicle numbers were decreased by 45%, 40%, and 17%, respectively, in PM2.5-exposed ovary-intact mice compared to controls (P < 0.05). The percentage of primary follicles with granulosa cells positive for the mitosis marker Ki67 was increased in the ovaries from PM2.5-exposed females versus controls (P < 0.05), consistent with increased recruitment of primordial follicles into the growing pool. Exposure to PM2.5 increased the percentages of primary and secondary follicles with DNA damage, assessed by γH2AX immunostaining (P < 0.05). Exposure to PM2.5 increased the percentages of apoptotic antral follicles, determined by TUNEL and activated caspase 3 immunostaining (P < 0.05). Removal of the ovaries and PM2.5-exposure exacerbated the atherosclerotic effects of hyperlipidemia in females (P < 0.05). While there were statistically significant changes in blood pressure and heart rate variability in PM2.5-compared to Air-exposed gonad-intact males and females and ovariectomized females, the changes were not consistent between exposure years and assessment methods. Conclusions These results demonstrate that subchronic PM2.5 exposure depletes the ovarian reserve by increasing recruitment of primordial follicles into the growing pool and increasing apoptosis of growing follicles. Further, PM2.5 exposure and removal of the ovaries each increase atherosclerosis progression in Apoe-/- females. Premature loss of ovarian function is associated with increased risk of osteoporosis, cardiovascular disease and Alzheimer’s disease in women. Our results thus support possible links between PM2.5 exposure and other adverse health outcomes in women.

Effect of the prenatal action of fulvestrant on the ovaries of the offspring of laboratory mice

Relevance. Fulvestrant is used for the treatment of breast cancer in combination with other drugs. The aim of the study was to determine the effect of the prenatal action of fulvestrant on the ovaries of the offspring of laboratory mice. Materials and Methods. The experimental animals were divided into 4 groups: intact, control and 2 experimental, 5 animals in each group. Injections were administered to females after fertilization at the gestational stage E 11.5 once intramuscularly. In the control group (n=5), sterile castor oil was administered at a dose of 0.8 mcg/kg. In the first experimental group (n=5), an antiestrogen was introduced in the form of an oil solution of fulvestrant 0.08 ml 0.0005% at a dose of 20 mcg/kg. In the second group (n=5), an antiestrogen was introduced in the form of an oil solution of fulvestrant 0.4 ml 0.0005% at a dose of 100 mcg/kg. Results and Discussion . The study revealed that in the ovaries when the drug was administered at a dose of 20 mcg/kg (F-20), the number of primordial follicles was reduced. Accordingly, the number of follicles of subsequent generations decreased. With the introduction of the drug fulvestrant 100 mcg/kg (F-100) on the section of the ovary, sclerosis of the stromal component is observed, accompanied by a rearrangement of the vascular network with signs of atresia and cystic degeneration of the follicular epithelium in the secondary and tertiary follicles, formed cysts are observed in the ovarian parenchyma. Conclusion. The prenatal effect of the drug fulvestrant on the maternal body during pregnancy leads to persistent structural changes in the ovaries of the offspring, manifested in the late stages of ontogenesis, which, in turn, can lead to violations of reproductive function. The depth and scale of these changes are dose-dependent.

Aloe vera increases collagen fibres in extracellular matrix and mRNA expression of peroxiredoxin-6 in bovine ovarian cortical tissues cultured in vitro

Summary In vitro culture of ovarian tissue containing primordial follicles is an important tool to study the initiation of follicular populations and to develop efficient culture systems to support in vitro follicle growth. Considering that in vitro culture favours oxidative stress, it is very important to supplement culture medium with antioxidant substances such as Aloe vera extract. This study aims to evaluate the effects of different concentrations of Aloe vera on the distribution of collagen fibres in the extracellular matrix, follicular activation, development and survival in bovine ovarian cortical tissues cultured in vitro, as well as on expression of mRNAs for antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), peroxiredoxin 6 (PRDX6) and glutathione peroxidase 1 (GPX1)]. To this end, ovarian cortical tissues were cultured for 6 days in α-MEM alone or supplemented with different concentrations of Aloe vera extract (1.0, 5.0, 10.0 or 50.0%). After culture, fragments were fixed and processed histologically to evaluate follicular morphology and activation, as well as the extracellular matrix by staining with picrosirius red. The levels of mRNA for SOD, CAT, PRDX6 and GPX1 in cultured ovarian tissues were evaluated by real-time polymerase chain reaction (PCR). Ovarian tissues cultured with 10.0 or 50.0% Aloe vera had higher percentages of collagen fibres than tissues cultured in control medium. A significant increase in developing follicles was observed in ovarian tissues cultured in α-MEM alone or supplemented with 10% Aloe vera when compared with fresh control or tissues cultured with 1.0% Aloe vera. Presence of Aloe vera did not influence the percentage of morphologically normal follicles when compared with control medium. Ovarian tissues cultured with 50.0% Aloe vera had higher percentages of morphologically normal follicles than those cultured with 10.0% Aloe vera. Furthermore, 10% Aloe vera significantly increased mRNA levels for PRDX6. In conclusion, 10.0% Aloe vera improves extracellular matrix distribution in cultured tissues and increases the expression of mRNA for PRDX6 after 6 days in vitro.

Insights into in vivo follicle formation: a review of in vitro systems

In vitro systems capable of reconstituting the process of mouse oogenesis are now being established to help develop further understanding of the mechanisms underlying oocyte/follicle development and differentiation. These systems could also help increase the production of useful livestock or genetically modified animals, and aid in identifying the causes of infertility in humans. Recently, we revealed, using an in vitro system for recapitulating oogenesis, that the activation of the estrogen signaling pathway induces abnormal follicle formation, that blocking estrogen-induced expression of anti-Müllerian hormone is crucial for normal follicle formation, and that the production of α-fetoprotein in fetal liver tissue is involved in normal in vivo follicle formation. In mouse fetuses, follicle formation is not carried out by factors within the ovaries but is instead orchestrated by distal endocrine factors. This review outlines findings from genetics, endocrinology, and in vitro studies regarding the factors that can affect the formation of primordial follicles in mammals.

Effects of Heat Stress on Follicular Physiology in Dairy Cows

Follicular organization starts during mid-to-late fetal life with the formation of primordial follicles. The bilateral interplay between the oocyte and adjoining somatic cells during follicular growth and ovulation may be sensitive to heat stress (HS). Mechanisms giving rise to pre-ovulatory temperature gradients across reproductive tissues are mostly regulated by the pre-ovulatory follicle, and because the cooling of the gonads and genital tract depends on a counter-current transfer system of heat, HS may be considered a major factor impairing ovulation, fertilization and early embryo development. There is evidence of a long-lasting influence of HS on oogenesis and final follicular maturation. Follicular stages that are susceptible to HS have not been precisely determined. Therefore, the aim of this review was to describe the influence of HS during the staged follicular development in dairy cattle, from the activation of primordial follicles to ovulation. Some clinical prospects are also considered.

Maintenance of quiescent oocytes by noradrenergic signals

All females adopt an evolutionary conserved reproduction strategy; under unfavorable conditions such as scarcity of food or mates, oocytes remain quiescent. However, the signals to maintain oocyte quiescence are largely unknown. Here, we report that in four different species – Caenorhabditis elegans, Caenorhabditis remanei, Drosophila melanogaster, and Danio rerio – octopamine and norepinephrine play an essential role in maintaining oocyte quiescence. In the absence of mates, the oocytes of Caenorhabditis mutants lacking octopamine signaling fail to remain quiescent, but continue to divide and become polyploid. Upon starvation, the egg chambers of D. melanogaster mutants lacking octopamine signaling fail to remain at the previtellogenic stage, but grow to full-grown egg chambers. Upon starvation, D. rerio lacking norepinephrine fails to maintain a quiescent primordial follicle and activates an excessive number of primordial follicles. Our study reveals an evolutionarily conserved function of the noradrenergic signal in maintaining quiescent oocytes.

Establishment and Mechanism Study of a Primary Ovarian Insufficiency Mouse Model Using Lipopolysaccharide

This study is aimed at establishing a lipopolysaccharide- (LPS-) induced primary ovarian insufficiency (POI) mouse model and investigating the underlying mechanism. C57BL/6N female mice were intraperitoneally injected with low-dose LPS (0.5 mg/kg) once daily for 14 days, high-dose LPS (2.5 mg/kg) twice weekly for 2 weeks, or cyclophosphamide (CTX; 150 mg/kg) once weekly for 2 weeks. Ovarian function was assessed by measuring the length of estrous cycle, the number of primordial follicles, and the levels of serum hormones. Expression and production of interleukin 1β (IL-1β) were determined to evaluate ovarian inflammation. Histopathological examination was performed to examine ovarian fibrosis. TUNEL assay was carried out to evaluate granulosa cell apoptosis. Western blotting was performed to measure the levels of inflammation-, fibrosis-, and apoptosis-related proteins in the mouse ovaries. Like CTX, both low- and high-dose LPS significantly impaired ovarian functions in mice, as evidenced by extended lengths of estrous cycles, reduced counts of primordial follicles, and alterations in the levels of serum hormones. Also, LPS promoted granulosa cell apoptosis and ovarian fibrosis in mice. However, LPS but not CTX promoted IL-1β expression and production in mice. Moreover, LPS but not CTX enhanced TLR, p-p65, p65, and MyD88 expression in mouse ovaries, suggesting that LPS differs from CTX in triggering ovarian inflammation. In general, continuous low-dose LPS stimulation was less potent than high-dose LPS to affect the ovarian functions. In conclusion, LPS may induce ovarian inflammation, fibrosis, and granulosa cell apoptosis and can be used to establish a POI model in mice.

A Nutraceutical approach to enhance Reproductive longevity and Ovarian health using Curcuma longa in wistar Rats

Aging is associated with various physiological, pathological and psychosocial alterations. This study evaluates the benefits of Curcumin by assessing reproductive aging indices and ovarian health in Wistar rats. Laboratory bred adult rats selected for the experiment. After 12 months of follow-up, the animals were grouped into Normal control rats, Sham control group, Curcumin-1(100 mg/kg body weight), Curcumin-2(200 mg/kg body weight) and Curcumin-3 (400 mg/kg body weight). For the duration of six months Curcumin dosage was administered. The experimental parameters included estrous cycle and histological evaluation of ovarian follicles. Data were analyzed using one-way ANOVA. The percentage of primordial follicles was significantly more (p<0.001) in all the groups when compared with other types of follicles. Prolonged increase (p=0.0001) in the Diestrus phase in animals treated with different dosages of Curcumin. The current study concludes that Curcumin, an active component of Curcuma longa contributes to the anti-aging properties.

XinJiaCongRongTuSiZiWan Protects TP-Induced Rats from Oxidative Stress Injury via Mitophagy Mediated PINK1/ Parkin Signaling Pathway

Background: Oxidative stress is one of main molecular mechanisms involved in toxicity of triptolide (TP). Although our group has discovered the effectiveness of XinJiaCongRongTuSiZiWan (XJCRTSZW) on premature ovarian failure (POF) and polycystic ovary syndrome (PCOS), whether the protective role of XJCRTSZW being associated with oxidative stress is still totally understood. Methods: Adult female Sprague-Dawley rats and human ovarian granulosa cell lines were treated with TP, and then treated with XinJiaCongRongTuSiZiWan (XJCRTSZW). Histological analysis and follicle count were executed using H&E staining. Hormone (E2, AMH, P, FSH and LH) concentrations, oxidative stress indicators (SOD and MDA), apoptosis rate, ATP content, mitochondrial membrane potential (MMP), cell viability, mitophagy and relative mRNA and protein levels (LC3-Ⅱ/LC3-Ⅰ, p62, Hsp60, PINK1 and Parkin) were detected by ELISA, commercial biochemical detection kits, flow cytometry, JC-1 staining, CCK-8, transmission electron microscope and western blotting respectively. Results: XJCRTSZW treatment observably ameliorated the TP-induced the pathological symptoms, including the decreased primordial follicles, primary follicles and secondary follicles numbers in the cortical area, the increased numbers of atretic follicles, necrotic and shedding, and nuclear constriction and collapse with cystic dilatation in vivo. Furthermore, XJCRTSZW treatment observably enhanced the TP-induced reduction of E2, AMH and P concentrations, SOD concentrations, ATP content, MMP, p62 and Hsp60 mRNA and protein level, but, diminished the TP-induced elevation of FSH and LH concentrations, MDA level, ROS level, apoptosis rate, mitophagy, and the mRNA and protein expression of LC3-Ⅱ/LC3-Ⅰ, PINK1 and Parkin both in vivo and in vitro. In addition, XJCRTSZW treatment markedly increased the TP-induced reduction of cell viability in vitro.Conclusion: XinJiaCongRongTuSiZiWan protects TP-induced rats from oxidative stress injury via mitophagy mediated PINK1/ Parkin signaling pathway.