ESR2 regulates indian hedgehog signaling in neonatal rat ovary

The transcriptional regulatory function of estrogen receptor β (ESR2) is essential for the regulation of primordial follicle activation (PFA). Increased PFA due to the loss of ESR2 becomes evident as early as postnatal day 8 (PND8). To identify the ESR2-regulated genes that control PFA, we performed RNA-seq analyses of wildtype, and Esr2 knockout (Esr2KO) neonatal rat ovaries collected on PND4, PND6, and PND8. Among the differentially expressed genes in Esr2KO ovaries, indian hedgehog (Ihh) displayed the highest downregulation among the ovary enriched genes. IHH regulated genes including Hhip as well as the steroidogenic enzymes were also downregulated in Esr2KO rat ovaries. Remarkably, the expression of Ihh in Esr2KO ovaries was not upregulated despite the high levels of Gdf9 and Bmp15, which are known regulators of Ihh expression in granulosa cells. Our findings suggest that indian hedgehog signaling in the neonatal rat ovary is dependent on ESR2.

Effect of Ethylene Glycol on Structural Integrity at Each Stage of Preantral Follicle Development Post Vitrification of Rat Ovary-Histological Analysis

The structure of follicular tissue affects the ability to maintain the structural integrity of follicles against cryoinjury post-vitrification. Histological analysis was conducted on the structural integrity of each stage of preantral follicles post-vitrification using 7.5% and 15.0% doses of ethylene glycol (EG), and ovarian sections with HE staining were observed using an Olympus CX21 microscope connected to Optilab 3.0 lens and Image Raster software. Analysis was conducted on the ovarian cortex in the tracing line area using polygon measure tools to obtain follicle density (follicles/mm2) and follicle index (%) data. The result showed that the EG group 7.5% (KP1) increased follicle density compared to the vitrified group (KKV) in primordial (15.83±1.77) and primary (22.94±8.51) stages. Meanwhile, KP2 (EG 15%) was in primordial (41.92±6.45), primary (11.69±1.95), secondary (33.48±3.63), and tertiary (5.93±0.69) stages. KP1 increased grade 3 follicle index compared to KKV in primary (27.66±2.34), secondary (32.41±6.99), and tertiary (25.00±5.00) stages. Meanwhile, KP2 was in primary (26.87±6.68) and tertiary (25.00±5.00) stages. Both doses of 7.5% and 15.0% EG were able to maintain structural integrity at certain stages of preantral follicles. Secondary and tertiary follicles are the best stages in maintaining grade 3 follicular integrity with the addition of 7.5% EG.

Neurotensin: A Neuropeptide induced by hCG in the Human and Rat Ovary during the Periovulatory Period

Neurotensin (NTS) is a tridecapeptide that was first characterized as a neurotransmitter in neuronal cells. The present study examined ovarian NTS expression across the periovulatory period in the human and the rat. Women were recruited into this study and monitored by transvaginal ultrasound. The dominant follicle was surgically excised prior to the LH surge (preovulatory phase) or women were given 250 μg hCG and dominant follicles collected 12-18 h after hCG (early ovulatory), 18-34 h (late ovulatory) and 44-70 h (postovulatory). NTS mRNA was massively induced during the early and late ovulatory stage in granulosa cells (15,000 fold) and theca cells (700 fold). In the rat, hCG also induced Nts mRNA expression in intact ovaries and isolated granulosa cells. In cultured granulosa-lutein cells (GLC) from IVF patients, NTS expression was induced 6 h after hCG treatment whereas in cultured rat granulosa cells NTS increased 4 h after hCG treatment. Cells treated with hCG signaling pathway inhibitors revealed that NTS expression is partially regulated in the human and rat GC by the epidermal-like growth factor (EGF) pathway. Human GLC and rat granulosa cells also showed that Nts was regulated by the PKA pathway along with input from the PI3K and MAPK pathways. The predominate NTS receptor present in human and rat granulosa cells was SORT1, whereas NTSR1 and NTSR2 expression was very low. Based on NTS actions in other systems, we speculate that NTS may regulate crucial aspects of ovulation such as vascular permeability, inflammation, and cell migration.

Morphological and Biochemical Changes in the Rat Ovaries Following Electromagnetic Field Exposure

PurposeThis study aims to investigate the effect of electromagnetic field (EMF) exposure which is environmental toxic agent on rat ovary. MethodsA total of 30 female Wistar albino rats are randomly divided into three groups (n=10) as Control, Sham, and EMF groups. The rats are not exposed any processes in Control group. The rats are kept in special cage for the same duration as in the EMF group without any EMF exposure in Sham group while the rats are exposed to 900 MHz EMF with a special mechanism in EMF group. At the end of day 28, the ovarian tissues are collected. Stereological and biochemical examinations are performed.ResultsConcerning the GSI values, there are statistical differences between the Control and EMF (p=0.001), and Sham and EMF (p=0.001) groups, respectively. There are also statistical differences between Control and EMF groups in terms of volumetric parameters including medullary, and follicular antral volumes. Regarding the biochemical parameters, there are statistically differences between the Control and EMF (p=0.000), and Sham and EMF (p=0.000) groups, respectively.ConclusionIt may be concluded that exposure to a 900-MHz EMF leads to changes in ovarian follicle volumes which may affect the ovarian reservoir.