Chicken postovulatory follicle

MicroRNAs (miRNAs) play a crucial role as transcription regulators in various aspects of follicular development, including steroidogenesis, ovulation, apoptosis, and gene regulation in poultry. However, there is a paucity of studies examining the specific impact of miRNAs on ovarian granulosa cells (GCs) across multiple grades in laying hens. Consequently, this study aims to investigate the roles of miRNAs in chicken GCs. By constructing miRNA expression profiles of GCs at 10 different time points, encompassing 4 pre-hierarchical, 5 preovulatory, and 1 postovulatory follicles stage, we identified highly expressed miRNAs involved in GC differentiation (miR-148a-3p, miR-143-3p), apoptosis (let7 family, miR-363-3p, miR-30c-5p, etc...

Ovarian follicle development is a complex and well-orchestrated biological process of great economic significance for poultry production. Specifically, understanding the molecular mechanisms underlying follicular development is essential for high-efficiency follicular development can benefit the entire industry. In addition, domestic egg-laying hens often spontaneously develop ovarian cancer, providing an opportunity to study the genetic, biochemical, and environmental risk factors associated with the development of this cancer...

Folliculogenesis is a complex biological process involving a central oocyte and its surrounding somatic cells. Three-dimensional chromatin architecture is an important transcription regulator; however, little is known about its dynamics and role in transcriptional regulation of granulosa cells during chicken folliculogenesis. We investigate the transcriptomic dynamics of chicken granulosa cells over ten follicular stages and assess the chromatin architecture dynamics and how it influences gene expression in granulosa cells at three key stages: the prehierarchical small white follicles, the first largest preovulatory follicles, and the postovulatory follicles...

Accumulating evidence has demonstrated the role of microRNAs (miRs) in the avian ovary. In this study, high-throughput transcriptome analyses were employed to study the differential miR expression profiles in the chicken ovary, aiming to reveal miR-targeting matrix metalloproteinase (MMP) expression during follicular growth, maturation, and atresia. Using tissues of chicken ovarian follicles at key steps of development (slow growing - white, the most recently recruited - small yellow, and preovulatory - F2) and regression (the third postovulatory), 14 small RNA (sRNA) libraries were constructed...

The postovulatory follicle (POF) in birds is an enigmatic structure, the function of which remains largely unknown. Previous studies on chickens have shown that removal of POFs leads to the postponement of oviposition and the disturbance of broody behavior. One suggestion is that POFs may secrete some crucial hormones or cytokines to act on reproductive organs. However, such secretions and their specific target organs remain to be identified. Here, we investigate the putative functions of POFs in promoting the development of prehierarchical follicles in chickens and explore the possible signaling mechanisms controlling these processes...

After ovulation in mammals, rupture of mature follicles is reorganized into the corpus luteum that secrets progesterone (P4 ) to stimulate endometrial development. The situation in birds differs considerably. Beyond ovulation the ruptured avian follicle forms a postovulatory follicle (POF) that is not considered analogous to mammalian corpus luteum. The function and regression mechanisms of avian POFs remain poorly understood. Here we investigated the changes in apoptotic and autophagic activities that were involved during POF degradation...

The study was undertaken to examine mRNA expression and localization of selected matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), and the activity of MMPs in chicken postovulatory follicles (POFs) during their apoptotic regression. Apoptotic cells and apoptosis-related caspase expression and activity were examined as well. Chickens were sacrificed 2 h and 21 h after ovulation, and five POFs (POF1 to POF5) were isolated from the ovaries. It was found that the number of apoptotic cells (TUNEL-positive) increased along with follicle regression...

Extracelluar matrix undergoes constant remodeling, cell-cell, and cell-matrix interactions during chicken ovarian follicle growth, which is coordinated by matrix metalloproteinases (MMPs), and their associated endogenous inhibitors (TIMPs). Transcriptome analysis revealed upregulation of MMP13 in sexually mature chicken ovaries. In this study, we found that the expression of MMP13 in chicken ovary was stably elevated from 60 d to 159 d, and was significantly higher at 159 d than at the other three developmental stages (P < 0...

Matrix metalloproteinases (MMPs) are a specific class of proteolytic enzymes that play critical roles in follicular development and luteinization in mammals. However, the role of MMPs in avian ovary remains largely unknown. We found that three MMP genes (MMP1, MMP3, and MMP9) were significantly up-regulated in 23-wk-old (laying phase) chicken ovaries compared with 6-wk-old ovaries (prepubertal phase). In reproductively active chicken ovary, MMP1 expression (both mRNA and protein) remained low in prehierarchical and preovulatory follicles but increased in postovulatory follicles (POFs)...

In the mammalian ovary, matrix metalloproteinase-2 (MMP-2) is thought to be involved in the regulated turnover of the extracellular matrix during the process of follicle development, ovulation and regression. Information concerning the role of MMP-2 in the chicken ovary is scarce. The present investigation was undertaken to determine the distribution of MMP-2 mRNA within the laying hen ovary as well as to define whether the expression of MMP-2 mRNA changes during the ovulatory cycle. Expression of MMP-2 mRNA in ovarian compartments was determined by RT-PCR analysis at two stages of the ovulatory cycle, i...

The study was undertaken to determine the effect of histamine on blood flow to the ovary and oviduct in the domestic hen (Gallus domesticus). Cardiac output and blood flow were measured with 86RbCl through the ovarian stroma, white ovarian follicles, yellow preovulatory follicles, postovulatory follicles and four oviductal parts: infundibulum, magnum, isthmus and shell gland 1 min and 5 min after histamine treatment. In comparison with control hens which received 0.9% NaCl, histamine significantly increased (by 21...

Melatonin (N-acetyl-5-methoxytryptamine), an indole hormone, regulates various biological functions through three different receptor subtypes (Mel-1a, Mel-1b, and Mel-1c). However, the distribution of different melatonin receptor subtypes in chicken reproductive tissues was not known. In the present investigation, the partial sequences of ovarian melatonin receptor subtypes (Mel-1a, Mel-1b, and Mel-1c) were characterized. Further, the expression profile of melatonin receptor subtypes in the granulosa and theca layers of different preovulatory and postovulatory follicles (POF) were studied by semi-quantitative RT-PCR...

Cyclooxygenase (COX) (PTGS) is the rate-limiting enzyme in the biosynthesis of prostaglandins. Two COX isoforms have been identified, COX-1 and COX-2, which show distinct cell-specific expression and regulation. Ovarian cancer is the most lethal gynecological malignancy and the disease is poorly understood due to the lack of suitable animal models. The laying hen spontaneously develops epithelial ovarian cancer with few or no symptoms until the cancer has progresses to a late stage, similar to the human disease...

BACKGROUND: The initial stages of development depend on mRNA and proteins accumulated in the oocyte, and during these stages, certain genes are essential for fertilization, first cleavage and embryonic genome activation. The aim of this study was first to search for avian oocyte-specific genes using an in silico and a microarray approaches, then to investigate the temporal and spatial dynamics of the expression of some of these genes during follicular maturation and early embryogenesis...

The mechanism of postovulatory follicle (POF) regression in birds is still poorly understood. In the current study, expression of IL-1beta, IL-6, GM-CSF, IFN-gamma, IL-2, IL-4, IL-13, chCXCLi2, chCCLi2, chCCLi4, chCCLi7, IL-10 and TGF-beta2 mRNAs was estimated in regressing POF by semi-quantitative RT-PCR. In addition, the changes in immune cell population, histological and apoptotic changes were also studied in regressing POF. The expression of cytokines (IL-1beta, IL-6, IL-10 and TGF-beta2) and chemokines (chCXCLi2, chCCLi2, chCCLi4 and chCCLi7) was upregulated in POFs, suggesting a role for these molecules in tissue regression...

Chicken postovulatory follicle (POF) regression occurs via the process of apoptosis. However, the signals and initiator pathways responsible for regression of the POF are unknown. In the current study, we examined gene expression patterns of various caspases (caspase-1, -2 and -3) involved in apoptosis by semi-quantitative RT-PCR. The percentage of apoptotic cells during POF regression was also quantified by flow cytometry. Expression of caspase-3 mRNA was noted in the largest preovulatory follicle (F1). However, the initiator caspases (caspase-1 and -2) were not expressed in F1...

Nitric oxide (NO) has recently emerged as a regulator of functional and structural regression in mammalian reproductive tissues. However, the role of NO in ovulation and postovulatory follicles (POF) that undergo regression in laying birds is unclear. In the present investigation, the expression profiles of iNOS mRNA, tissue NO levels and the percentage of apoptotic cells were studied in the regressing chicken postovulatory follicle (POF). The postovulatory follicles gradually lost weight during its regression and reached the lowest weight on POF5...

Proteolytic activities are essential for follicular growth, ovulation, as well as for luteal formation and regression. Using suppression subtractive hybridization (SSH), a novel mouse ovary-selective gene (termed protease serine 35, Prss35) was identified. Analysis of the mouse genome database using the Prss35 sequence led to the identification of a homologous protease (protease serine 23, Prss23). PRSS35 possesses general features that are characteristic of serine (Ser) proteases, but is unique in that the canonical Ser that defines this enzyme family is replaced by a threonine (Thr)...

A cause-effect relationship between ovulation and common (surface) epithelial ovarian cancer has been suspected for many years. The ovarian surface epithelium apparently becomes exposed to genotoxins that are generated during the ovulatory process. Intensive egg-laying hens readily develop ovarian carcinomatosis. Indeed, elevated levels of potentially mutagenic 8-oxo-guanine adducts were detected in avian ovarian epithelial cells isolated from the apical surfaces and perimeters of pre-and postovulatory follicles, respectively...

To study the potential involvement of inhibin A (inhA), inhibin B (inhB), activin A (actA) and follistatin (FS) in the recruitment of follicles into the preovulatory hierarchy, growing follicles (ranging from 1 mm to the largest designated F1) and the three most recent postovulatory follicles (POFs) were recovered from laying hens (n=11). With the exception of <4 mm follicles and POFs, follicle walls were dissected into separate granulosa (G) and theca (T) layers before extraction. Contents of inhA, inhB, actA and FS in tissue extracts were assayed using specific two-site ELISAs and results are expressed per mg DNA...