Kit和KitL在卵泡发育过程中的作用

在卵泡内,卵母细胞及其周围的颗粒细胞之间的旁分泌作用对哺乳动物的卵子发生和卵泡发育是非常重要的。研究表明颗粒细胞衍生的KitL(Kitligand,stem cell factor,SCF)与卵母细胞和膜细胞产生的Kit的相互作用在PGCs迁移和增殖、卵泡发育过程中有重要的作用。本文重点阐述了由KitL通过Kit激活的PI3K(phosphatidylinositol 3-kinase,磷脂酰肌醇-3-激酶)通路,它对卵母细胞生长、凋亡和卵泡早期发育起重要的调节作用。     

促卵泡素对鸡等级前卵泡细胞发育的影响

实验研究了鸡等级前卵泡颗粒细胞和膜细胞的发育及促卵泡素(FSH)对其增殖的调控作用。形态学观察显示小白卵泡只有1层颗粒细胞,大白卵泡出现2层颗粒细胞,而小黄卵泡和大黄卵泡中则有多层颗粒细胞。结果表明:卵泡颗粒细胞和膜细胞的密度和细胞层厚度随着卵泡发育的等级而增加。卵泡体外悬浮培养表明,FSH显著刺激小黄卵泡和大黄卵泡中颗粒细胞的增殖,但对膜细胞无显著促增殖作用。由此推测,FSH通过刺激颗粒细胞的增殖促使等级前卵泡进入等级发育。     

MicroRNA及其对哺乳动物繁殖的影响

卵巢功能的正常维持有赖于卵巢生殖细胞和体细胞之间的相互作用及若干卵巢自分泌和旁分泌的调节.这些调节物质调控卵巢内不同的细胞活动,包括细胞生长、分化和凋亡,从而对卵泡的发育起着至关重要的作用.Micro-RNAs(miRNAs)是一种小的、非编码、21～25 nt长的单链小分子RNA,近年来科学家们发现其在基因表达转录后水平的调控发挥了重要作用.鼠上的研究显示,miRNAs在卵母细胞成熟和卵巢卵泡发育过程中有调控功能.人上的研究也表明,miRNAs影响颗粒细胞中特定的基因表达,并参与卵巢癌的形成和发展.本文将对miRNAs的生物合成,及其在哺乳动物繁殖系统中的表达,正常和病理情况下miRNAs在繁殖系统中可能的调控作用作一综述.     

颗粒细胞生长发育及其在卵泡发生中的作用

本文简述了影响颗粒细胞分裂化以及生长与机能的因素，阐明了颗粒细胞在卵泡发生及随后的卵母细胞受精与胚胎发生中的作用，并探讨了颗粒细胞在卵母细胞体外成熟中的应用。     

绵羊卵泡发育过程中关键信号通路研究进展

卵泡从原始卵泡发育为成熟卵泡，直至排卵、黄体发育等过程都受到精密的调控，产生大量的优势卵泡是绵羊产多羔及实现快速扩繁的关键因素。研究发现，相关信号通路和转录因子通过影响绵羊卵泡中卵母细胞、颗粒细胞的生长，进而调控卵泡的发育成熟，对这些信号通路进行深入了解，有助于探索卵泡发育的调控机制，早日实现绵羊高效繁育。Notch是卵泡发育过程中发挥重要作用的高度保守信号通路，PI3K/AKT/mTOR信号通路各成员都是广泛存在于细胞内的信号转导分子，在卵泡发育早期发挥了主要作用，还有间隙连接（gap junction，GJ）和跨带突触（transzonal projections，TZPs）等物理连接方式，在细胞间的交流通讯起到重要作用。作者详细介绍了Notch信号通路、PI3K/AKT/mTOR信号通路、间隙连接及跨带突触的结构功能在绵羊卵泡发育中的调控作用，为进一步探明绵羊卵泡发育的调控机制提供参考。     

细胞自噬对动物卵泡发育调控的研究进展

卵泡是雌性哺乳动物发挥其繁殖能力的基础,其发育是一个动态的过程,主要涉及原始卵泡的形成、卵泡的募集、优势卵泡的选择、成熟卵泡的排卵以及排卵后卵泡的黄体化。卵泡发育的整个过程受内分泌系统、细胞自噬、细胞凋亡等的调控。自噬是一种进化上保守的应激反应过程,通过将细胞内物质包裹形成自噬体并传递到溶酶体中进行降解,以帮助细胞维持胞内物质代谢平衡,其在卵泡发育的过程中发挥着重要作用,一方面它能够通过降解或回收受损的蛋白质或有害代谢产物缓解应激造成的卵泡损伤,另一方面它又通过产生大量自噬体导致细胞器过度降解而引起卵泡闭锁。自噬对卵泡发育的调控需要PI3K-Akt-mTOR、MAPK-ULK1、ERK1/2、Sirt1-FOXO1-Atg7等多种经典信号通路的参与,这些信号通路在激素、氧化应激、细胞饥饿等的刺激下,通过独立作用或相互作用促进或抑制自噬调控卵泡细胞的生理活动。目前已知不同的自噬水平对卵泡细胞的存活具有不同作用,但关于决定细胞能否存活的自噬水平的研究还比较少。此外,自噬对卵泡发育调控的研究主要集中在颗粒细胞中,而对卵母细胞的成熟和卵泡膜细胞的作用的报道较少。文章简述了自噬在卵巢储备的形成、...     

连接蛋白Cx43和Cx37在卵泡发育中的作用

卵泡中的颗粒细胞通过间隙连接彼此交流,也与卵母细胞相互联系.连接蛋白是组成间隙连接的基本结构单位,其中Cx43和Cx37是卵泡发育所必需的.Cx43介导的间隙连接偶联通道对于胚胎生殖嵴的发育和出生后的卵泡发生都是必不可少的.Cx37除了对卵母细胞和颗粒细胞之间的交流发挥作用外,还能在紧邻卵母细胞的颗粒细胞之间形成交流通道,缺失Cx37会影响到有腔卵泡的发育,并且卵母细胞不能发育至成熟,故Cx43和Cx37对卵泡发育至关重要.     

鸡卵泡选择及分子调控作用机制研究进展

鸡卵泡选择能否有序进行是直接影响等级卵泡数量以及产蛋持续性的重要因素。本文主要综述了家禽卵泡选择发育过程及其影响因素，并提炼阐述卵泡选择过程中颗粒细胞的作用，以及各信号通路之间的串扰调控功能，丰富禽类繁殖调控基础理论，为鸡的繁殖调控研究提供参考价值。     

前列腺素对禽类等级卵泡发育的影响

前列腺素是一类由花生四烯酸通过环氧化酶途径合成的脂类介导物。在哺乳动物排卵、受精、胚泡植入、蜕膜化、子宫平滑肌收缩、黄体退化及卵泡发育过程中起重要作用。对于家禽,前列腺素促进其产卵和子宫收缩;在产卵中期,卵巢静脉血浆中前列腺素的浓度为外周血浆浓度的5～20倍。这种高剂量、脉冲式分泌的前列腺素不仅能促进家禽成熟卵泡的排卵,而且可作为促性腺激素的第二信使介导颗粒细胞对cAMP的反应,促进了等级前卵泡颗粒细胞的增殖,进而在优势卵泡的选择过程中起重要作用。     

miRNA调控动物卵泡发育研究进展

雌性动物的繁殖潜力基于卵泡的发育，该过程受到复杂的基因网络调控。microRNA （miRNA）是一种短的、非编码RNA，在转录后调控基因表达。在过去的十年中，对动物卵泡中非编码RNA的深入研究揭示了miRNA在卵泡发育过程中的关键作用。作者简述了雌性动物卵泡发育过程，总结了miRNA调控卵泡发育的作用机制，包括原始卵泡的激活、生长卵泡的发育选择、卵泡颗粒细胞和卵泡膜细胞的生长调控等，分析了卵泡液外囊泡携带miRNA的功能。但当前卵泡miRNA的研究多集中在细胞敲低模型研究，敲除模型研究较少，因此增加细胞及活体敲除模型的研究有助于更好地了解miRNA在卵泡发育中的功能。本综述可为深入解析雌性动物繁殖性状调控的分子机制提供参考。     

家禽卵泡颗粒细胞体外培养方法研究进展

家禽卵巢中颗粒细胞在卵泡发育和闭锁中起着重要作用,包括信号传递、营养供给以及离子平衡等。卵泡颗粒细胞的增殖与分化自身也受到生殖激素和细胞因子的综合调节,其作用机制是当前研究热点。家禽卵泡颗粒细胞的体外培养可作为研究繁殖生理调节的理想细胞模型。本文对家禽卵泡颗粒细胞的体外培养研究现状及颗粒细胞在卵泡生长发育和闭锁中的作用进行简要概述,并总结了原代颗粒细胞体外培养模型的建立方法。     

Conditions affecting growth and developmental competence of mammalian oocytes in vitro

Mammalian ovaries contain a large number of oocytes at different stages of growth. To utilize potential female gametes, it is important to develop culture systems that permit oocytes to achieve full growth and competence in order to undergo maturation, fertilization and development. The desired culture systems should meet at least the following three conditions: (i) oocytes remain healthy and functional so that they can execute intrinsic programs that direct their growth and development; (ii) granulosa cells that are adjacent to oocytes proliferate efficiently to prevent oocytes from becoming denuded; and (iii) granulosa cells maintain (and develop) appropriate associations with oocytes during the culture period. For this reason, several systems have been developed, and they can be classified into four categories based on the structure and components of the follicle/oocyte–granulosa cell complex and the location of the oocyte in the physical organization of the complex. The resultant diverse morphologies are due to multiple factors, including the method for initial isolation of follicles, the culture substrate, and hormones and other factors added into the medium. It is important to find an optimal combination of such factors involved in the process to facilitate future research efforts.     

Role of oocyte‐derived paracrine factors in follicular development

Mammalian oocytes secrete transforming growth factor β (TGF‐β) superfamily proteins, such as growth differentiation factor 9 (GDF9), bone morphogenetic protein 6 (BMP6) and BMP15, and fibroblast growth factors (FGFs). These oocyte‐derived paracrine factors (ODPFs) play essential roles in regulating the differentiation and function of somatic granulosa cells as well as the development of ovarian follicles. In addition to the importance of individual ODPFs, emerging evidence suggests that the interaction of ODPF signals with other intra‐follicular signals, such as estrogen, is critical for folliculogenesis. In this review, we will discuss the current understanding of the role of ODPFs in follicular development with an emphasis on their interaction with estrogen signaling in regulation of the differentiation and function of granulosa cells.     

牛腔前卵泡体外培养前后质量评定

采用台盼蓝染色、相差显微镜观察以及透射电镜方法对体外培养前后牛腔前卵泡活力进行评定。结果表明,台盼蓝染色和相差显微镜观察检测卵泡活力有一定的误检率,超微结构检测能够客观、真实地反映腔前卵泡健康状况,可作为评定腔前卵泡培养系统优劣的一个可靠手段。在实际应用中,相差显微镜观察与超微结构评定相结合可发挥良好作用。     

Lysophosphatidic acid expression in theca cells depends on the type of bovine ovarian follicle

Lysophosphatidic acid (LPA) exerts various actions on the mammalian reproductive system. In cows, LPA stimulates the synthesis and secretion of luteotropic factors in the ovary, which affects the growth and development of ovarian follicles. The role of LPA in granulosa cells, oocyte and oocyte‐cumulus complex (COC) has previously been investigated; but its role in the theca layer, which is an important structural and functional component of the ovarian follicle, is still unclear. The goal of this study was to investigate the expression of LPA in theca cells originating from different bovine ovarian follicle types. Theca cells were separated from healthy, transitional and atretic ovarian follicles, based on intrafollicular estradiol: progesterone ratios. LPA concentration in the follicular fluid (FF) in different follicle types was measured, and expression of the enzymes responsible for LPA synthesis (autotaxin [AX], phospholipase A2 [PLA2]) and receptors for LPA (LPAR1‐4) were determined. The obtained results confirmed the follicle‐type dependent presence of LPA in the FF of the bovine ovarian follicles. The highest concentration of LPA was detected in follicles classified as healthy and dominant. LPAR1‐4, PLA2 and AX expression in theca cells in all of the types of follicles examined were detected at mRNA and protein level. These results suggest that theca cells can be a source of LPA synthesis other than granulosa cells and COCs, as well as the target for its action in the bovine ovarian follicle, with PLA2 and LPAR4 playing major roles in LPA synthesis and action.