卵泡FSH受体mRNA的表达及其对卵母细胞体外培养成熟率的影响

本研究采用RT-PCR技术检测了猪大、中、小卵泡颗粒细胞中FSH受体(FSHR)mRNA的表达差异,比较和分析了受体表达差异及其对卵母细胞体外成熟培养的影响。结果表明大、中、小卵泡中颗粒细胞都有FSHR mRNA表达,大卵泡的颗粒细胞与小、中卵泡的颗粒细胞FSHR mRNA相对表达量有显著差异(P<0.05),中、小卵泡的颗粒细胞FSHR mRNA相对表达量之间无显著差异(P>0.05)。不同大小卵泡卵母细胞体外成熟培养结果表明,小卵泡与大、中卵泡比较,卵丘细胞扩展率和第一极体排出率差异显著(P<0.05)。这表明猪不同大小卵泡颗粒细胞FSHR mRNA的表达量与其卵母细胞体外培养成熟率呈相关性,进一步证实FSHR在猪卵泡及卵母细胞发育中起着重要作用。     

TACE激酶在猪排卵过程中的作用机制

促黄体激素(LH)诱导猪卵泡排卵过程包括卵泡壁的破裂、颗粒细胞黄体化、卵丘细胞扩展和卵母细胞减数分裂成熟。LH受体主要在排卵前卵泡的颗粒细胞中表达,排卵刺激后表达水平明显降低。颗粒细胞和卵丘细胞表达的EGF样因子可以激活EGFR-MAPK3/1在这2种细胞中的通路。EGF样因子是由信号序列、跨膜区域和EGF区域组成,并且由特异性酶刺激释放EGF区域与EGFR互作诱导排卵过程。TACE/ADAM17是一种EGF样因子的蛋白水解酶,在FSH/LH刺激的颗粒细胞和卵丘细胞中表达并激活EGFR-MAPK3/1通路。应用特异性抑制剂或siRNA抑制技术而降低TACE/ADAM17的表达活性,则会抑制颗粒细胞黄体化、卵丘细胞扩展以及卵母细胞的成熟过程。因此,TACE/ADAM17是诱导猪排卵过程的主效基因。     

BMP-6对猪卵母细胞体外成熟的影响

为研究BMP-6在猪卵泡发育过程中的作用,采用免疫荧光和Western blot技术检测BMP-6在猪排卵前卵泡卵母细胞、颗粒细胞以及卵泡液中的表达;在猪卵母细胞体外成熟培养过程中分别添加5、25及50 ng/mL BMP-6蛋白,观察其对猪卵母细胞在体外成熟过程中的影响。结果表明,猪排卵前卵泡的卵母细胞和颗粒细胞以及卵泡液中均存在BMP-6蛋白,体外添加不同浓度的BMP-6蛋白均能明显促进猪卵母细胞体外成熟,说明BMP-6在猪卵泡发育及猪卵母细胞的成熟过程中发挥作用。     

牛卵巢卵泡Smad9表达模式的研究

本研究旨在探究Smad9在牛卵巢卵泡中的表达模式,为研究Smad9的功能奠定基础。从屠宰场获取牛卵巢,分离得到小卵泡(2 mm≤直径≤4 mm)、中卵泡(4 mm直径8 mm)、大卵泡(直径≥8 mm),用免疫组织化学技术对不同直径卵泡的Smad9蛋白进行定位分析;通过机械分离法分离卵泡颗粒细胞,用qPCR和Westernblotting技术检测Smad9在小卵泡、中卵泡、大卵泡颗粒细胞中的相对表达量。结果显示:在牛的卵泡中,Smad9在颗粒细胞和膜细胞层中表达;小卵泡和中卵泡颗粒细胞中Smad9mRNA转录本相对丰度低于大卵泡颗粒细胞(P0.01),而中卵泡颗粒细胞内Smad9 mRNA转录本相对丰度低于小卵泡(P0.05);中卵泡和小卵泡颗粒细胞中Smad9蛋白的表达量低于大卵泡(P0.01),中卵泡颗粒细胞中Smad9蛋白表达量是小卵泡的0.9倍(P0.05)。综上,Smad9主要在牛卵泡颗粒细胞层中表达,且大卵泡表达量极显著高于小卵泡和中卵泡。     

绵羊卵巢卵泡FoxO1表达模式的研究

本研究旨在探究Fox O1在绵羊卵巢卵泡的表达模式。屠宰场取卵巢获得卵泡,分为小卵泡(直径≤3 mm)、中卵泡(3 mm<直径<5 mm)、大卵泡(直径≥5 mm)3组。利用免疫组化技术对不同直径卵泡的FoxO1进行定位分析,通过机械分离法分离卵泡颗粒细胞,qRT-PCR和Western blotting技术检测FoxO1在小、中、大卵泡颗粒细胞的表达量。结果显示:在绵羊卵泡中,FoxO1表达于颗粒细胞层;中卵泡的FoxO1 mRNA表达量高于小卵泡和大卵泡(P<0.01),小卵泡FoxO1mRNA表达量高于大卵泡(P<0.01);FoxO1蛋白在大卵泡的表达量低于小卵泡和中卵泡(P<0.01),但小卵泡和中卵泡表达量差异不显著。综上表明,FoxO1在绵羊卵泡颗粒细胞层表达,且在大卵泡中的表达量极显著低于小卵泡和中卵泡。     

BDNF和TrkB蛋白在5月龄和10月龄雌猫子宫和卵巢表达的研究

为探讨脑源性神经营养因子(BDNF)及其受体酪氨酸激酶B(TrkB)在幼龄和初情期猫子宫和卵巢的表达规律,试验采用免疫组织化学方法检测BDNF和TrkB在5月龄、10月龄雌猫子宫和卵巢上的表达差异。结果表明:BDNF和TrkB在原始卵泡和各级卵泡中均有表达,BDNF在窦状卵泡的颗粒细胞、膜细胞和卵母细胞中表达明显,10月龄蛋白表达强度强于5月龄,颗粒细胞的蛋白表达增强明显;TrkB表达部位与BDNF基本一致,但卵泡液和卵母细胞表面出现强表达,10月龄表达强度与5月龄基本一致。此外在猫卵巢发现含有多个卵母细胞的卵泡。BDNF在子宫内膜、腺体和小血管均有表达,10月龄子宫的蛋白表达强度高于5月龄,BDNF在10月龄子宫肌层有表达、5月龄无表达;TrkB在10月龄子宫内膜、腺体、肌层弱表达,小血管强表达,TrkB蛋白除了在5月龄子宫的小血管强表达外其他部位几乎无表达。     

C型利钠肽及其受体在水牛卵泡中的表达分析

为了探明C型利钠肽（C-type natriuretic peptide,CNP）及其受体（natriuretic peptide receptor,NPR）在水牛卵泡中的表达模式,本研究首先采用实时荧光定量PCR技术检测水牛卵巢中利钠肽家族主要成员A型、B型、C型利钠肽（ANP、BNP、CNP）及其Ⅰ型、Ⅱ型受体（NPR1、NPR2）的mRNA表达情况,然后利用免疫组化技术对水牛卵泡中CNP及NPR2蛋白进行定位,最后利用实时荧光定量PCR技术检测颗粒细胞和卵丘细胞中CNP及NPR2的mRNA表达规律。结果显示,水牛卵巢主要表达CNP及NPR2,且在各级卵泡中均有表达,其中,CNP主要在壁层颗粒细胞中表达,NPR2主要在卵丘细胞中表达;颗粒细胞上CNP mRNA表达水平显著高于卵母细胞周围的卵丘细胞（P<0.05）,而卵丘细胞上NPR2 mRNA表达水平显著高于颗粒细胞（P<0.05）。综上所述,在利钠肽主要家族成员和受体中,CNP和NPR2在水牛卵巢中呈现强表达,CNP主要在壁层颗粒细胞中表达,而NPR2主要在卵母细胞周围的卵丘细胞中表达。     

EGF基因在动物卵泡发育过程中的研究进展

表皮生长因子(EGF)是表皮上生长家族的重要调节因子之一,可促进细胞增殖分化、调控细胞的衰老以及诱导肿瘤的发生。在动物卵巢卵泡的研究中发现,EGF可以有效地抑制卵泡细胞的凋亡、促进颗粒细胞的增殖和卵母细胞的成熟,因此近年来受到了越来越多的学者的关注。为了进一步认识EGF基因对各级卵泡的调节作用,文章拟从EGF基因的结构、对卵泡发育的作用机理等角度进行阐述,为研究EGF基因参与调控动物卵泡发育过程的作用机制提供参考。     

RT-PCR技术检测绵羊卵巢内Ghrelin的表达

为了明确Ghrelin在绵羊卵巢有腔卵泡上是否存在表达,本研究利用实时定量RT-PCR技术检测了绵羊卵巢有腔卵泡内的卵母细胞、卵丘细胞和壁层颗粒细胞的Ghrelin蛋白的表达量情况。结果揭示绵羊卵巢有腔卵泡内各类型细胞Ghrelin mRNA的相对表达量大致相同。绵羊卵巢有腔卵泡内各类型细胞Ghrelin蛋白的表达及Ghrelin mRNA的表达模式,尤其是卵母细胞中的表达,揭示这一新型分子在绵羊卵巢上具有潜在的调控作用。     

BMP-4mRNA在兔卵巢中的定位及其在卵母细胞体外成熟培养中的表达研究

为探索骨形态发生蛋白4(BMP-4)在兔卵巢中的表达模式,揭示其在卵母细胞成熟和卵泡发育以及黄体化等过程中的作用,本研究采用原位杂交方法测定BMP-4mRNA在兔卵巢中的表达定位,利用实时荧光定量RT-PCR方法检测BMP-4mRNA在卵母细胞体外成熟培养过程中的表达变化。结果表明:BMP-4 mRNA在各级非闭锁卵泡均有低水平表达,在闭锁的初级卵泡、次级卵泡、近成熟卵泡中有极强或较强的表达。兔卵母细胞在体外成熟过程中有BMP-4 mRNA的微量表达,但是与0 h相比较,成熟培养4、8、24 h卵母细胞中BMP-4mRNA表达量没有明显变化,而16 h的表达量明显降低,且与0、4、8、24 h存在极显著差异(P<0.01)。由此推测,兔BMP-4在卵巢卵泡生长发育过程中微量表达可能起黄体化抑制因子作用,并且与BMP-15相互关联对卵丘扩展发挥重要作用。另外,可能高活力的BMP-4以卵母细胞的自分泌方式参与了兔卵巢卵泡的闭锁机制。     

The localization and expression of epidermal growth factor and epidermal growth factor receptor in bovine ovary during oestrous cycle

Epidermal growth factor (EGF) is one of the important regulatory factors of EGF family. EGF has been indicated to effectively inhibit the apoptosis of follicular cells, to promote the proliferation of granulosa cells and the maturation of oocytes, and to induce ovulation process via binding to epidermal growth factor receptor (EGFR). However, little is known about the distribution and expression of EGF and EGFR in cattle ovary especially during oestrous cycle. In this study, the localization and expression rule of EGF and EGFR in cattle ovaries of follicular phase and luteal phase at different time points in oestrous cycle were investigated by using IHC and real-time qPCR. The results showed that EGF and EGFR in cattle ovary were mainly expressed in granulosa cells, cumulus cells, oocytes, zona pellucida, follicular fluid and theca folliculi externa of follicles. The protein and mRNA expression of EGF/EGFR in follicles changed regularly with the follicular growth wave both in follicular and in luteal phase ovaries. In follicular phase ovaries, the protein expression of EGF and EGFR was higher in antral follicles than that of those in other follicles during follicular growth stage, and the mRNA expression of EGFR was also increased in stage of dominant follicle selection. However, in luteal phase ovaries, the growth of follicles was impeded during corpus luteum development under the action of progesterone secreted by granular lutein cell. The mRNA and protein expressions of EGF and EGFR in ovarian follicles during oestrous cycle indicate that they play a role in promoting follicular development in follicular growth waves and mediating the selection process of dominant follicles.     

Gene expression and immunolocalization of fibroblast growth factor 2 in the ovary and its effect on the in vitro culture of caprine preantral ovarian follicles

This study quantified Fibroblast growth factor 2 (FGF-2) mRNA and localized FGF-2 protein in different categories of follicles isolated from goat ovaries. In addition, we verified the effects of this factor on the in vitro culture of preantral follicles isolated from goats. For mRNA quantification, we performed real-time PCR using primordial, primary and secondary follicles, as well as cumulus-oocyte complexes (COCs) and mural granulosa and theca cells of small and large antral follicles. For FGF-2 protein localization, the ovaries were subjected to conventional immunohistochemical procedures. Preantral follicles were isolated and cultured in vitro for 12 days in either control (basic) or supplemented with FGF-2 medium. The expression of FGF-2 mRNA was detected in all categories of follicles and there was no difference in preantral follicles and COCs or granulosa/theca cells from small and large antral follicles. However, in large antral follicles, COCs showed expression levels significantly lower than in granulosa/theca cells (p < 0.05). We observed moderate expression of FGF-2 protein in preantral follicles but not in granulosa cells of primordial follicles and theca cells of secondary follicles. In both small and large antral follicles, strong, moderate and weak staining was observed in oocytes, granulosa and theca cells, respectively. The addition of FGF-2 caused a significant increase in the daily follicular growth rate compared to the control group. We conclude that FGF-2 mRNA is expressed throughout follicular development and that its protein can be found in different patterns in preantral and antral follicles. Furthermore, FGF-2 increases the follicular growth rate in vitro.     

Expression Analysis of C-type Natriuretic Peptide and Its Receptor in Buffalo Follicles

In order to investigate the expression pattern of C-type natriuretic peptide（CNP）and its receptors（NPR）in buffalo follicles,firstly,the mRNA expression level of ANP,BNP,CNP,NPR1 and NPR2 in ovary were assayed by Real-time quantitative PCR;Secondly,the protein expression of CNP and NPR2 in buffalo follicles were detected by immunohistochemical stainning method;Lastly,the mRNA expression level of CNP and NPR2 in granule cells and cumulus cells were assayed by Real-time quantitative PCR.The results showed that CNP gene and its receptor NPR2 mainly expressed in buffalo ovary,the protein of CNP and NPR2 expressed in all stages of follicles,CNP mainly expressed in mural granulosa cells and NPR2 primarily presented in cumulus cells,the mRNA expression of CNP gene in granule cells was significantly higher than cumulus cells（P<0.05),whereas the mRNA expression of NPR2 gene in cumulus cells was significantly higher than granule cells（P<0.05).In conclusion,among the main members of natriuretic peptides and its receptors,CNP and NPR2 presented strong expression in buffalo ovary.CNP mainly expressed in mural granulosa cells,but NPR2 primarily presented in cumulus cells which arounding oocytes.     

Expression of nitric oxide synthase-3 in porcine oocytes obtained at different follicular development

The present study was designed to determine the localization of nitric oxide synthase-3 (NOS-3) in porcine follicles during follicular development. A 130-kDa NOS-3 protein was found with greater frequency much in the oocytes than in the cumulus cells, as revealed by Western blotting analysis. The content of NOS-3 in the oocyte was higher in large follicles (> 7-mm diameter) than in small follicles (< 2-mm). The data by Western blotting showed the same pattern as the observations obtained from the immunohistochemical studies, in which the periphery of the oocyte stained strong positive. The inner surface cell layer of granulosa cells and cumulus cells were positive staining, especially in large antral follicles. In the primordial follicles, NOS-3 was restricted to the cytoplasm of oocytes, and no stained product was observed in the nucleus of oocytes or granulosa cells. A significant synthesis of NO by oocytes was observed in the presence of ionomycin, but not in the absence of ionomycin, indicating that oocyte NOS-3 functions in response to transient elevations in the intracellular calcium level. We concluded that NOS-3 is expressed in the oocyte from the primordial follicular stage to antral follicular stage, and that it is functional at least in the antral follicles.     

Androgen receptor mRNA expression in the bovine ovary

Previous studies have shown that androgen receptor (AR) is expressed in granulosa cells of healthy, growing ovarian follicles in rats and primates. However, AR expression in the bovine ovary has not been examined. Therefore, a 346-base pair segment of the bovine AR was cloned and sequenced. Using a ribonuclease protection assay, AR expression was detected in total RNA from bovine ovarian cortex. Expression (absence or presence) of AR mRNA was detected by in situ hybridization in bovine ovarian cortex. Follicles (n = 32) were classified as follows: type 1 (1 layer of flattened granulosa cells), type 2 (1-1.5 layers of cuboidal granulosa cells), type 3 (2-3 layers of granulosa cells), type 4 (4-6 layers of cuboidal granulosa cells and formation of thecal layer), and type 5 (>6 layers of cuboidal granulosa cells, defined theca layer, and antrum formation). Frequency of AR mRNA expression increased (P < 0.001) as follicles entered the growing pool. Expression of AR mRNA was absent in type 1 follicles (n = 8), but present in the granulosa cells of 41% of type 2 follicles (n = 12). In types 3-5 follicles, AR mRNA expression was present in granulosa cells of 100% of follicles examined (n = 4, 4, and 4, respectively) and was greater than type 1 follicles (P = 0.002). These data provide evidence of AR mRNA expression in bovine follicles and suggest that AR mRNA increases during early follicle development.