Long-term effects of methamphetamine exposure in adolescent mice on the future ovarian reserve in adulthood

Trans-generational effects of parental exposure to drugs of abuse on offspring memory functions

Recent evidence reported that parental-derived phenotypes can be passed on to the next generations. Within the inheritance of epigenetic characteristics allowing the transmission of information related to the ancestral environment to the offspring, the specific case of the trans-generational effects of parental drug addiction has been extensively studied. Drug addiction is a chronic disorder resulting from complex interactions among environmental, genetic, and drug-related factors. Repeated exposures to drugs induce epigenetic changes in the reward circuitry that in turn mediate enduring changes in brain function. Addictive drugs can exert their effects trans-generally and influence the offspring of addicted parents. Although there is growing evidence that shows a wide range of behavioral, physiological, and molecular phenotypes in inter-, multi-, and trans-generational studies, transmitted phenotypes often vary widely even within similar protocols. Given the breadth of literature findings, in the present review, we restricted our investigation to learning and memory performances, as examples of the offspring's complex behavioral outcomes following parental exposure to drugs of abuse, including morphine, cocaine, cannabinoids, nicotine, heroin, and alcohol.

Single-nucleus transcriptome profiling of prefrontal cortex induced by chronic methamphetamine treatment

Background

Methamphetamine (METH) addiction causes a huge burden on society. The prefrontal cortex (PFC), associated with emotion and cognitive behaviours, is also involved in addiction neurocircuitry. Although bulk RNA sequencing has shown METH-induced gene alterations in the mouse PFC, the impact on different cell types remains unknown.

Aims

To clarify the effects of METH treatment on different cell types of the PFC and the potential pathways involved in METH-related disorders.

Methods

We performed single-nucleus RNA sequencing (snRNA-seq) to examine the transcriptomes of 20 465 nuclei isolated from the PFC of chronic METH-treated and control mice. Main cell types and differentially expressed genes (DEGs) were identified and confirmed by RNA fluorescence in situ hybridization(FISH).

Results

Six main cell types were identified depending on the single-cell nucleus sequencing; of particular interest were the mature oligodendrocytes in the PFC. The DEGs of mature oligodendrocytes were enriched in the myelin sheath, adenosine triphosphate (ATP) metabolic process, mitochondrial function and components, and so on. The messenger RNA levels of Aldoc and Atp5l (FISH) and the protein level of the mitochondrial membrane pore subunit TOM40 (immunofluorescence) decreased in the mature oligodendrocytes. Fast blue staining and transmission electron microscopy image indicated myelin damage, and the myelin thickness decreased in METH brains.

Conclusions

snRNA-seq reveals altered transcriptomes of different cell types in mouse PFC induced by chronic METH treatment, underscoring potential relationships with psychiatric disorders.

Oxidative stress and mitochondrial dysfunction of granulosa cells in polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is one of the leading causes of anovulatory infertility in women, affecting 5%-15% of women of reproductive age worldwide. The clinical manifestations of patients include ovulation disorders, amenorrhea, hirsutism, and obesity. Life-threatening diseases, such as endometrial cancer, type 2 diabetes, hyperlipidaemia, hypertension, and cardiovascular disease, can be distant complications of PCOS. PCOS has diverse etiologies and oxidative stress (OS) plays an important role. Mitochondria, as the core organelles of energy production, are the main source of reactive oxygen species (ROS). The process of follicular growth and development is extremely complex, and the granulosa cells (GCs) are inextricably linked to follicular development. The abnormal function of GCs may directly affect follicular development and alter many symptoms of PCOS. Significantly higher levels of OS markers and abnormal mitochondrial function in GCs have been found in patients with PCOS compared to healthy subjects, suggesting that increased OS is associated with PCOS progression. Therefore, the aim of this review was to summarize and discuss the findings suggesting that OS and mitochondrial dysfunction in GCs impair ovarian function and induce PCOS.

Mechanism of quercetin on the improvement of ovulation disorder and regulation of ovarian CNP/NPR2 in PCOS model rats

PURPOSE

To investigate the effects of quercetin on ovulation disorder and expression of androgen receptor (AR) and C-type natriuretic peptide (CNP) / Natriuretic Peptide Receptor 2 (NPR2) in dehydroepiandrosterone (DHEA)-induced polycystic ovary syndrome (PCOS) rat model.

METHODS

DHEA was used to construct the PCOS rat model. After intervention with quercetin, metformin, and AR, the estrous cycle, ovarian and uterine weight of rats were measured. The morphological changes of ovarian and uterine were detected by hematoxylin-eosin staining (HE staining). Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured by Enzyme linked immunosorbent assay (ELISA). Immunohistochemical detection of interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), B-cell lymphoma-2 (BCL-2), BCL2-Associated X (Bax) and AR expression in ovarian. Determination of the expression of CNP and NPR2 mRNA by qRT-PCR. Chromatin immunocoprecipitation (ChIP) was used to detect the ability of AR to bind to CNP or NPR2 promoter.

RESULTS

The results showed that quercetin could significantly reduce the expression of Testosterone (T) , Estradiol (E₂) , LH, Bax, IL-1β, IL-6 and TNF-α, increase the expression of FSH and Bcl-2, inhibit the expression of AR, regulate the expression of CNP / NPR2 gene and protein by affecting the combination of AR with the specific sequence of CNP and NPR2 gene promoters, restore the maturation of oocyte and ovulation.

CONCLUSION

The results suggest that quercetin can alleviate the hormone, metabolic and ovulatory aberrations caused by PCOS, and provide experimental basis for the clinical application of quercetin in PCOS.

Lead exposure activates the Nrf2/Keap1 pathway, aggravates oxidative stress, and induces reproductive damage in female mice

Lead, a common metallic contaminant, is widespread in the living environment, and has deleterious effects on the reproductive systems of humans and animals. Although numerous toxic effects of lead have been reported, the effects and underlying mechanisms of the impacts of lead exposure on the female reproductive system, especially oocyte maturation and fertility, remain unknown. In this study, mice were treated by gavage for seven days to evaluate the reproductive damage and role of Nrf2-mediated defense responses during lead exposure. Lead exposure significantly reduced the maturation and fertilization of oocytes in vivo. Additionally, lead exposure triggered oxidative stress with a decreased glutathione level, increased amount of reactive oxygen species, and abnormal mitochondrial distribution. Moreover, lead exposure caused histopathological and ultrastructural changes in oocytes and ovaries, along with decreases in the activities of catalase, glutathione peroxidase, total superoxide dismutase, and glutathione-S transferase, and increases in the levels of malonaldehyde in mouse ovaries. Further experiments demonstrated that lead exposure activated the Nrf2 signaling pathway to protect oocytes against oxidative stress by enhancing the transcription levels of antioxidant enzymes. In conclusion, our study demonstrates that lead activates the Nrf2/Keap1 pathway and impairs oocyte maturation and fertilization by inducing oxidative stress, leading to a decrease in the fertility of female mice.

Smoke, alcohol and drug addiction and female fertility

BACKGROUND

Considerable interest has been gathered on the relevant impact of preventable factors, including incorrect lifestyle and unhealthy habits, on female fertility. Smoking, alcohol and addictive drugs consumption represent a major concern, given the broad range of diseases which might be favored or exacerbated by these dependable attitudes. Despite the well-characterized effects of prenatal exposure on pregnancy outcomes and fetus health, a substantial proportion of women of reproductive age is still concerned with these habits. At present, the impact of smoke, alcohol and addictive drugs on women fertility, and, particularly, the specific targets and underlying mechanisms, are still poorly understood or debated, mainly due to the scarcity of well-designed studies, and to numerous biases.

OBJECTIVE

The current review will provide a comprehensive overview of clinical and experimental studies in humans and animals addressing the impact of smoke, alcohol and addictive drugs on female fertility, by also embracing effects on ovary, oviduct, and uterus, with particular reference to primary endpoints such as ovarian reserve, steroidogenesis, ovulation and menstrual cycle, oviduct function and uterus receptivity and implantation. A brief focus on polycystic ovary syndrome and endometriosis will be also included.

METHODS

A Pubmed literature search was performed with selected keywords; articles were individually retrieved by each author. No limitation was set for publication date. Articles in languages other than English were excluded. Additional articles were retrieved from references list of selected manuscripts.

RESULTS AND CONCLUSIONS

Currently, the most consistent evidences of a detrimental effect of smoke, alcohol and addictive drugs on specific domains of the female reproductive function are provided by experimental studies in animals. Overall, clinical studies suggest that smoking is associated to decreased fertility, although causal inference should be further demonstrated. Studies addressing the effect of alcohol consumption on female fertility provide conflicting results, although the majority reported lack of a correlation. Extremely scarce studies investigated the effects of addictive drugs on female fertility, and the specific actions of selected drugs have been difficult to address, due to multidrug consumption.

Withdrawal from chronic treatment with methamphetamine induces anxiety and depression-like behavior in mice

Methamphetamine (METH) is an illicit psychostimulant that is widely abused. After producing extreme pleasure, METH abuse leads to negative emotional states during withdrawal in clinical survey. However, the mood behavioral consequences of withdrawal from chronic METH exposure in animal experiments and related mechanisms have not been clarified yet. The aim of this study was to investigate the anxiety and depression-like phenotype in mice induced by withdrawal from chronic METH treatment and the potential molecular mechanism. We found that withdrawal from chronic METH treatment increased the immobility time during the forced swimming test and decreased central activities in open field test, indicating increased anxiety and depression-like behavior. Additional experiments showed that expression of brain-derived neurotrophic factor (BDNF), phosphorylated tropomyosin receptor kinase B (p-TrkB), phosphorylated extracellular signal-related kinase 1/2 (p-ERK1/2) and phosphorylated cAMP-response element binding protein (p-CREB) were decreased in the hippocampus and prefrontal cortex of mice in METH group and the level of mitogen activated protein kinase phosphatase-1 (MKP-1) was increased. Combined, our data show that withdrawal from chronic METH exposure induces anxiety and depression-like behavior associated with aberrant changes of proteins in BDNF-ERK-CREB pathway, providing new evidence for the involvement of BDNF pathway in the negative emotional states induced by withdrawal from METH.

Rapamycin Prevents cyclophosphamide-induced Over-activation of Primordial Follicle pool through PI3K/Akt/mTOR Signaling Pathway in vivo

Background

Primordial follicular depletion has thought to be a common adverse effect of chemotherapy especially for female of reproductive age. The study aimed to evaluate the protective effect of rapamycin on the primordial follicles and its potential mechanism for patients receiving chemotherapy.

Methods

8-week old BALB/c female mice were randomly assigned into four groups (control; rapamycin; cyclophosphamide; and rapamycin combined with cyclophosphamide). Hematoxylin staining, immunohistochemical, TUNEL, western blotting and ELISA were employed to assess inter-group differences using Student’s t-test and Mann-Whitney test.

Results

Cyclophosphamide depleted the follicular reserve and induced the phosphorylation of the key proteins of PI3K/Akt/mTOR pathway in mice in a dose-dependent manner. Co-treatment with rapamycin significantly reduced primordial follicle loss at all cyclophosphamide dose groups and prevent the follicle growth wave caused by cyclophosphamide treatment (P < 0.05). TUNEL staining showed that no apoptosis occured in the primordial follicles in all groups and fewer apoptosis in large growing follicles were observed in ovaries from rapamycin + cyclophosphamide group compared to that received cyclophosphamide alone. Serum anti-Müllerian hormone (AMH) was significantly reduced in cyclophosphamide alone group, in contrast to the normal level in rapamycin + cyclophosphamide group. Compared to p-Akt/Akt and p-mtor/mtor, p-rps6/rps6 was significantly decreased in rapamycin + cyclophosphamide group (P < 0.05), indicating that rapamycin attenuated the increased level of phosphorylation of rpS6 after cyclophosphamide treatment.

Conclusions

Rapamycin can prevent the primordial follicle activation induced by cyclophosphamide through PI3K/Akt/mTOR signaling pathway and thus plays a role in preserving the follicle pool. These results suggest that rapamycin may be an effective protection for ovarian function during chemotherapy, which means a new nonsurgical application for protection of ovarian reserve and prevention of POF.