Treatment of porcine ovarian follicles with tert-butyl hydroperoxide as an ovarian senescence model in vitro

Ovarian aging is the main reason of female reproductive problems. Excessive oxidative stress can induce ovarian senescence and follicular atresia, thereby reducing the reproductive performance. Follicles were divided into five groups for in vitro culture based on the duration of stimulation with tert-butyl hydroperoxide (t-BHP)-control group and groups 1 h, 2 h, 6 h, and 12 h. The results revealed that the ratio of progesterone (P4) to estradiol (E2) was increased after 24 and 36 h of follicle culture, shifting follicles toward atresia (P < 0.05). Stimulated by 200 μM t-BHP, follicles showed progressive aging phenotype. Senescence-associated β-galactosidase staining (SA-β-Gal) showed a significant increase in the number of positive cells (P < 0.05). Reactive oxygen species were also significantly upregulated (P < 0.05). t-BHP treatment for 6 h induced significant increases in Caspase 3, P53, and Foxo1 mRNA and protein levels (P < 0.05) and significant decreases in SOD mRNA and protein levels (P < 0.05). Transcriptome sequencing analysis of the follicles showed that the aged and treatment groups were clustered together in hierarchical clustering. Correlation analysis indicated significant changes at the transcriptome level in the treatment groups versus the control group. The common differentially expressed genes in the treatment groups were enriched in three growth-factor signaling pathways associated with cell proliferation and apoptosis (P53, mTOR, and MAPK). In conclusion, induction of follicular senescence by treatment with 200 μM t-BHP for 6 h is an effective in vitro model to simulate ovarian senescence in sows.

Impact of adrenocorticotropin hormone administration on the endocrinology, estrus onset, and ovarian function of weaned sows

Chronic stress affects the reproductive health of mammals; however, the impact of adrenocorticotropin hormone (ACTH) level elevation during chronic stress on the reproduction of weaned sows remains unclear. In this study, nine weaned sows with the same parturition date were randomly divided into control group (n = 4) and ACTH group (n = 5). Each group received intravenous administration of ACTH three times daily for 7 days. Blood samples were collected every 3 h after injection. A radioimmunoassay was used to measure the concentrations of cortisol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P₄) and estradiol-17β (E₂) in the blood. Estrus was determined according to changes in the vulva and the boar contact test. The mRNA expressions of glucocorticoid receptor, FSH receptor, LH receptor (LHR) in the corpus luteum (CL) were detected by qRT-PCR. The results showed that ACTH administration substantially delayed the initiation of estrus and the pre-ovulatory LH peak. The sows of control group ovulated within 10 days and the ovulation rate was 100%, while it was 60% in the ACTH group. Two sows of ACTH group showed pseudo-estrus. The E₂ concentrations significantly decreased in the ACTH group at 36 h, 42 h and 66 h of the experimental period. The P₄ concentrations in the ACTH group significantly decreased at 132, 138, and 147 h of the experimental period. ACTH significantly reduced the LHR mRNA expression in CLs. In conclusion, long-term repeated ACTH administration affects the endocrinology, estrus onset, and ovarian function of weaned sows.

Longitudinal Expression of Testicular TAS1R3 from Prepuberty to Sexual Maturity in Congjiang Xiang Pigs

Simple Summary

Taste receptor type 1 subunit 3 (T1R3), a sweet/umami taste receptor, is widely expressed from the tongue to the testis, and testis expression is associated with male sterility. In Congjiang Xiang pigs, T1R3 is expressed in elongating/elongated spermatids and Leydig cells in a stage-dependent manner during postnatal development and the spermatogenic cycle. T1R3 may contribute to regulation of spermatid differentiation and Leydig cell function, and may therefore help limit the incidence of various male reproductive pathologies.

Abstract

Testicular expression of taste receptor type 1 subunit 3 (T1R3), a sweet/umami taste receptor, has been implicated in spermatogenesis and steroidogenesis in mice. We explored the role of testicular T1R3 in porcine postnatal development using the Congjiang Xiang pig, a rare Chinese miniature pig breed. Based on testicular weights, morphology, and testosterone levels, four key developmental stages were identified in the pig at postnatal days 15–180 (prepuberty: 30 day; early puberty: 60 day; late puberty: 90 day; sexual maturity: 120 day). During development, testicular T1R3 exhibited stage-dependent and cell-specific expression patterns. In particular, T1R3 levels increased significantly from prepuberty to puberty (p < 0.05), and expression remained high until sexual maturity (p < 0.05), similar to results for phospholipase Cβ2 (PLCβ2). The strong expressions of T1R3/PLCβ2 were observed at the cytoplasm of elongating/elongated spermatids and Leydig cells. In the eight-stage cycle of the seminiferous epithelium in pigs, T1R3/PLCβ2 levels were higher in the spermatogenic epithelium at stages II–VI than at the other stages, and the strong expressions were detected in elongating/elongated spermatids and residual bodies. The message RNA (mRNA) levels of taste receptor type 1 subunit 1 (T1R1) in the testis showed a similar trend to levels of T1R3. These data indicate a possible role of T1R3 in the regulation of spermatid differentiation and Leydig cell function.

Mesenchymal Stem Cell Therapy Using Human Umbilical Cord in a Rat Model of Autoimmune-Induced Premature Ovarian Failure

Premature ovarian failure (POF) is one of the principal causes of female infertility, and although its causes are complex and diverse, autoimmune deficiency may be involved. Human umbilical cord mesenchymal stem cells (UCMSCs) can be used for tissue regeneration and repair. Therefore, the present study was designed to determine the role of UCMSCs in immune factor-induced POF in rats. In this study, different concentrations of UCMSCs were injected into induced POF rats. Ovarian functions were examined by evaluating the estrus cycle, follicular morphology, hormonal secretion, and the proliferation and apoptosis of granulosa cells. Our results showed that the estrus cycle of rats returned to normal and follicular development was significantly improved after transplantation of UCMSCs. In addition, serum concentrations of 17-estradiol (E2), progesterone (P4), and anti-Müllerian hormone (AMH) increased significantly with treatment. Transplantation of UCMSCs also reduced the apoptosis of granulosa cells and promoted the proliferation of granulosa cells. All of these improvements were dose dependent. Furthermore, the results of related gene expression showed that transplanted human UCMSCs upregulated the expression of Bcl-2, AMH, and FSHR in the ovary of POF rats and downregulated the expression of caspase-3. These results further validated the potential mechanisms of promoting the release of cell growth factors and enhancing tissue regeneration and provide a theoretical basis for the clinical application of stem cells in the treatment of premature ovarian failure.

Exosomal miRNA-17-5p derived from human umbilical cord mesenchymal stem cells improves ovarian function in premature ovarian insufficiency by regulating SIRT7

Premature ovarian insufficiency (POI) is clinically irreversible in women aged over 40 years. Although numerous studies have demonstrated satisfactory outcomes of mesenchymal stem cell therapy, the underlying therapeutic mechanism remains unclear. Exosomes were collected from the culture medium of human umbilical cord mesenchymal stem cells (hUMSCs) and assessed by electron microscopy and Western blot (WB) analysis. Then, exosomes were added to the culture medium of cyclophosphamide (CTX)-damaged human granulosa cells (hGCs), and the mixture was injected into the ovaries of CTX-induced POI model mice before detection of antiapoptotic and apoptotic gene expression. Next, the microRNA expression profiles of hUMSC-derived exosomes (hUMSC-Exos) were detected by small RNA sequencing. The ameliorative effect of exosomal microRNA-17-5P (miR-17-5P) was demonstrated by miR-17-5P knockdown before assessment of ovarian phenotype and function, reactive oxygen species (ROS) levels and SIRT7 expression. Finally, SIRT7 was inhibited or overexpressed by RNA interference or retrovirus transduction, and the protein expression of PARP1, γH2AX, and XRCC6 was analyzed. The ameliorative effect of hUMSC-Exos on POI was validated. Our results illustrated that hUMSC-Exos restored ovarian phenotype and function in a POI mouse model, promoted proliferation of CTX-damaged hGCs and ovarian cells, and alleviated ROS accumulation by delivering exosomal miR-17-5P and inhibiting SIRT7 expression. Moreover, our findings elucidated that miR-17-5P repressed PARP1, γH2AX, and XRCC6 by inhibiting SIRT7. Our findings suggest a critical role for exosomal miR-17-5P and its downstream target mRNA SIRT7 in hUMSC transplantation therapy. This study indicates the promise of exosome-based therapy for POI treatment.

Roles of poly (ADP-ribose) polymerase 1 activation and cleavage in induction of multi-oocyte ovarian follicles in the mouse by 3-nitropropionic acid

3-nitropropionic acid (3-NPA) is known to be a mitochondrial toxin produced by plants and fungi, which may produce DNA damage in cells. However, studies of its reproductive toxicology are lacking. We know that poly(ADP-ribose) polymerase (PARP) plays an important role in a large variety of physiological processes and is involved in DNA repair pathways. The present study was therefore aimed at exploring the involvement of PARP-1 activation and cleavage after 3-NPA stimulation in female mice. We observed an increased number of atretic follicles and multi-oocyte follicles (MOFs) after treatment with 3-NPA and serum concentrations of 17β-oestradiol and progesterone were significantly reduced. Our results provide evidence that PARP-1 cleavage and activational signals are involved in pathological ovarian processes stimulated by 3-NPA. In addition, total superoxide dismutase, glutathione peroxidase and catalase activities were significantly increased, whereas succinate dehydrogenase was decreased in a dose-dependent manner. Results from our in vitro study similarly indicated that 3-NPA inhibited the proliferation of mouse granulosa cells and increased apoptosis in a dose-dependent manner. In summary, 3-NPA induces granulosa cell apoptosis, follicle atresia and MOFs in the ovaries of female mice and causes oxidative stress so as to disrupt endogenous hormonal systems, possibly acting through PARP-1 signalling.

Observation of Parthanatos Involvement in Diminished Ovarian Reserve Patients and Melatonin's Protective Function Through Inhibiting ADP-Ribose (PAR) Expression and Preventing AIF Translocation into the Nucleus

Diminished ovarian reserve (DOR) is characterized by the depletion of the ovarian pool, which leads to reductions in oocyte quality and quantity. Studies have suggested that ovarian reserve or ovarian aging is tightly related to apoptosis. However, the cell death mechanism is not comprehensively understood. Parthanatos, a type of poly [ADP-ribose] polymerase 1(PARP1)-dependent and apoptosis-inducing factor (AIF)-mediated cell death, plays a crucial role in various disorders. In the present study, we aimed to investigate whether parthanatos is involved in the pathogenesis of DOR. We recruited 40 patients (20 DOR patients and 20 normal ovarian reserve (NOR) patients) and examined PAR expression and AIF translocation in their isolated cumulus GCs (granulosa cells) by fluorescence microscopy. Our results demonstrated that PAR expression and AIF nuclear translocation were significantly higher in cumulus GCs of DOR patients, suggesting that PARP1-dependent cell death may be associated with DOR pathophysiology. Moreover, we tested the protective function of melatonin on hydrogen peroxide (H₂O₂)-induced parthanatos in human ovarian cancer (IGROV1) cells. Our results demonstrated that H₂O₂ treatment of IGROV1 cells led to excessive protein PARylation and AIF translocation into the nuclei. Melatonin effectively inhibits PARylation, blocks translocation of AIF into the nucleus, and consequently decreases the risk of parthanatos in cumulus GCs.

Spontaneous Development of Dental Dysplasia in Aged Parp-1 Knockout Mice

Poly(ADP-ribose) polymerase (Parp)-1 catalyzes polyADP-ribosylation using NAD⁺ and is involved in the DNA damage response, genome stability, and transcription. In this study, we demonstrated that aged Parp-1^-/- mouse incisors showed more frequent dental dysplasia in both ICR/129Sv mixed background and C57BL/6 strain compared to aged Parp-1^+/+ incisors, suggesting that Parp-1 deficiency could be involved in development of dental dysplasia at an advanced age. Computed tomography images confirmed that dental dysplasia was observed at significantly higher incidences in Parp-1^-/- mice. The relative calcification levels of Parp-1^-/- incisors were higher in both enamel and dentin (p < 0.05). Immunohistochemical analysis revealed (1) Parp-1 positivity in ameloblasts and odontoblasts in Parp-1^+/+ incisor, (2) weaker dentin sialoprotein positivity in dentin of Parp-1^-/- incisor, and (3) bone sialoprotein positivity in dentin of Parp-1^-/- incisor, suggesting ectopic osteogenic formation in dentin of Parp-1^-/- incisor. These results indicate that Parp-1 deficiency promotes odontogenic failure in incisors at an advanced age. Parp-1 deficiency did not affect dentinogenesis during the development of mice, suggesting that Parp-1 is not essential in dentinogenesis during development but is possibly involved in the regulation of continuous dentinogenesis in the incisors at an advanced age.

Neonatal genistein exposure disrupts ovarian and uterine development in the mouse by inhibiting cellular proliferation

Soy-based formula contains high concentrations of the isoflavone genistein. Genistein possesses estrogenic and tyrosine kinase inhibitory activity and interferes with cellular proliferation and development. To date, the acute and chronic effects of genistein on ovarian and uterine development have not been fully elucidated. In this study, mice at postnatal day 1 were subcutaneously injected with 100 mg/kg genistein for 10 consecutive days, and then their ovaries and uteri were collected on days 10, 21, and 90. Histological evaluation was performed after hematoxylin and eosin staining. The proliferating activity was indicated by the proliferating indicator protein Ki67. Results showed that the subcutaneous injection of genistein to neonatal mice induced the formation of multi-oocyte follicles and delayed the primordial follicle assembly in the ovaries. Genistein significantly enlarged the cross-sectional area of the uterine cavity and wall and disrupted the regularity between the uterine stroma and myometrium. Genistein exposure inhibited proliferative activity because fewer Ki67-positive nuclei were detected in ovarian and uterine cell populations than in the control. Furthermore, most ovaries from adult mice given neonatal genistein were without corpora lutea, and there appeared to be cystic follicles and hypertrophy of the theca, and cortical and medullary layers. Considering the high concentration of isoflavone in soy-based infant formulas and livestock feed, we suggest that the use of isoflavone-rich diets in humans and livestock receive closer examination.

Melatonin mitigates bisphenol A-induced estradiol production and proliferation by porcine ovarian granulosa cells in vitro

Melatonin plays a crucial role in the amelioration of reproductive toxicity induced by endocrine-disrupting chemicals. However, very few studies have investigated the mitigating effects of melatonin on BPA-induced dysfunction in porcine granulosa cells. In the present study, primary granulosa cells were cultured in serum-low conditions with bisphenol A (BPA) (10 μM) with or without melatonin (100 μM), followed by evaluation of estradiol synthesis and cell proliferation. Our results showed that BPA significantly increased estradiol concentration and granulosa cell proliferation. Interestingly, melatonin co-incubation reduced the high levels of estradiol in porcine ovarian granulosa cells induced by BPA stimulation. Furthermore, melatonin co-incubation also attenuated BPA-induced proliferation as shown by a decline in the Ki67-positive cell ratio and PCNA expression level. However, treatment with melatonin-alone did not dramatically reduce estradiol levels or expression of proliferative regulatory protein markers (Ki67, PCNA). We hypothesize that the regulation by melatonin of estradiol biosynthesis and cellular proliferation is highly correlated with BPA stimulation. In conclusion, this study first showed that melatonin mitigated BPA-induced estradiol increase and proliferation in porcine ovarian granulosa cells in vitro. Our results suggest that melatonin may be a promising pharmacologic agent for preventing the potential reproductive toxicity caused by endocrine-disrupting chemicals.

Thyroid hormones alter estrous cyclicity and antioxidative status in the ovaries of rats

To expand our understanding of the roles of thyroid hormones on female reproduction, we induced hypo- and hyper-T rat models to investigate the roles of thyroid hormones on estrous cyclicity, as well as the antioxidative status in the ovaries of rats. In the current study, our data show that hypothyroidism (hypo-T) and hyperthyroidism (hyper-T) led to significantly reduced body weights and ovarain weights and delayed vaginal opening day. For hyper-T, thyroxine (T4), tri-iodothyronine (T3), progesterone (P4) and follicle-stimulating hormone (FSH) were significantly increased, while estradiol (E2) and luteinizing hormone (LH) were significantly decreased. For hypo-T rats, serum levels of total T4 and T3, E2, P4, FSH and LH were significantly increased, while concentrations of E2 and LH were significantly decreased. For ovary morphology, the numbers of secondary and antral follicles were significantly decreased with more atretic antral follicles and less corpora lutea in both hyper- and hypo-T groups. Both hyper-T and hypo-T treatment significantly decreased the expressions of thyroid hormone receptor α1 in the ovary. Hypo-T significantly reduced nitric oxide (NO), total NO synthase (tNOS), inducible NOS and constitutive NOS activities, but hyper-T increased them. For antioxidative parameters, hypo-T and hyper-T treatment significantly increased malondialdehyde (MDA) contents. The activities of both glutathione peroxidase (GSH-Px) and catalase (CAT) significantly decreased in the hypo-T group but increased in the hyper-T group. Total superoxide dismutase (T-SOD) activity was significantly increased in the hyper-T group. In summary, thyroid hormones alter estrous cyclicity and antioxidative status in the ovary of the rat may act through the NOS signaling pathway.

Roles of SIRT1 in granulosa cell apoptosis during the process of follicular atresia in porcine ovary

Ovarian follicular atresia is characterized by granulosa cell apoptosis, however, the exact mechanism is still unclear. Sirtuin 1 (SIRT1) is a NAD(+)-dependent deacetylase, which is associated with apoptosis in several of cell types, but its exact role in ovarian granulosa cell apoptosis is not clearly defined. In present study, we identified the involvement of SIRT1 in the process of follicle degeneration, which is known as "follicular atresia", both from in vivo models and cell culture data. The results of immunohistochemistry showed that SIRT1 was widely detected in non-apoptotic granulosa cells of follicles, but significantly decreased during the process of granulosa cell apoptosis. Quantitative real-time PCR and Western blot analysis showed that the expression levels of SIRT1 mRNA and protein were increased (P<0.05) during follicular atresia. In order to provide more evidences elucidating the roles of SIRT1 during the process of follicular atresia, granulosa cells were cultured in vitro with resveratrol which acts as a potent activator of SIRT1. Results showed that resveratrol caused a dose-dependent increase in both SIRT1 mRNA and protein levels. Meanwhile, apoptotic rate of granulosa cell was increased (P<0.01) in a dose-dependent manner. Additionally, resveratrol significantly increased the expression levels of Caspase-3 (P<0.01) and Bax mRNA (P<0.01), while Bcl-2 mRNA level was significantly decreased (P<0.01). Thus, our results suggest that SIRT1 may play important roles in the regulation of granulosa cell apoptosis during follicular atresia in porcine ovary.

Protective effects of Big-leaf mulberry and physiological roles of nitric oxide synthases in the testis of mice following water immersion and restraint stress

Big-leaf mulberry is a new hybrid plant from the application of cell engineering technology, but its effect in stress-induced testicular dysfunction is unknown. Nitric oxide (NO) is a tiny, highly reactive lipophilic molecule produced by nitric oxide synthases (NOS). Three isoforms of NOS (neuronal NOS, inducible NOS and endothelial NOS) have been identified. Our aim was to investigate the effect of water immersion and restraint stress (WIRS) on NOS in the testis, and the effect of Big-leaf mulberry to protect against WIRS. The activity and expression of NOS, and total antioxidant capacity (T-AOC) in the mouse testis of different treatment groups (non-WIRS, 3 h-WIRS, WIRS-recovery) were examined. Histological analysis of WIRS-induced testicular damage and immunohistochemical staining of NOS were also analyzed. Results demonstrated that WIRS-exposed mice produced several injuries and showed an increased iNOS and eNOS mRNA expression in testes, whereas pretreatment with Big-leaf mulberry down-regulated iNOS and eNOS mRNA expressions and up-regulated T-AOC activities. Immunohistochemical studies showed that both iNOS and eNOS were localized in germ cells, spermatozoa and blood vessels in addition to Leydig cells and Sertoli cells, but nNOS was not present in these areas. In conclusion, our results suggested that Big-leaf mulberry exerted a protective effect on WIRS-induced testicular dysfunction, and iNOS and eNOS appeared to exert an important action in mouse testes exposed to WIRS.