犬黄体功能调控机制研究进展

犬黄体具有异于其他家畜的生理结构和功能表现,其中最特别的是犬缺乏急性黄体溶解机制。犬黄体发生过程受催乳素、促黄体素和前列腺素E₂的复杂调控,溶解退化过程则对其他家畜主要的溶黄体激素--前列腺素F_2α不敏感。而黄体的存留对母犬的生殖活动却具有重要的意义,其自分泌或旁分泌的类固醇激素也在妊娠调控和发情周期的更迭中发挥重要作用。犬黄体的退化机制尚未明确,但国外已有包括被动退化在内的诸多假说。此外,黄体是为数不多具有完整生命周期的功能性组织（或器官）,其发生过程、功能实现和衰老溶解都在周而复始地进行,这对炎症反应、癌症发生和细胞凋亡等研究都具有重要的参考价值。作者综述了犬黄体的发生和退化过程中调控机制的研究进展,旨在为进一步深入研究犬黄体发生和退化的分子机制提供研究背景和理论依据。     

小鼠发情周期中黄体大小及细胞的数量变化规律

为探索发情周期黄体中细胞的形态分布及数量变化规律,采用HE染色法对发情周期中小鼠黄体的体积大小、黄体细胞的形态分布特征、细胞大小及不同大小细胞所占比例、细胞数量以及卵巢的体积大小等变化规律进行了较系统的研究。结果表明,黄体Ⅰ期中,细胞总数较多,体积中等的黄体细胞比例较高;黄体Ⅱ期中,细胞总数最多,体积中等的黄体细胞比例较高;黄体Ⅲ期中,细胞总数较多,体积中等的黄体细胞比例较高;而黄体Ⅳ期中,细胞总数最少,体积偏小的黄体细胞数量最多。通过静态数据分析,得出小鼠卵巢、黄体发育及其与小鼠发情周期阶段之间的动态关系,并为新的黄体细胞分类体系的建立和计算机模拟构建周期性黄体的三维立体构象提供了依据。     

牛黄体中心腔的研究

本研究检查了706枚牛的不同生长阶段黄体的形态和内分泌,目的是查明黄体中心腔与不孕症是否有关。黄体中心腔的出现率为:生长黄体42.1％(80/190),成熟黄体33.7％(126/374),退化黄体11..％(7/63),妊娠黄体5.1％(4/79)。不论黄体有腔无腔对于发情周期中的卵泡数没有关系。与无腔黄体相比,有腔黄体中,1型黄体细胞占的份额较多,2型黄体细胞较少。这个结果说明黄体有腔无腔功能是有差别的,但黄体有腔不是病理现象。     

妊娠山羊黄体组织中ghrelin的表达

运用组织学和免疫组化方法对不同妊娠时期山羊黄体的组织学结构及ghrelin的分布规律进行了研究,结果表明:黄体外覆结缔组织性被膜,实质主要由粒性(大)黄体细胞和膜性(小)黄体细胞组成;在各时期均存在大黄体细胞的退化现象,退化黄体细胞数量随周期进程逐渐增多,结构变化表现为:细胞形态多变,胞质呈强嗜酸性,胞核固缩或碎裂.ghrelin阳性反应主要位于被膜和黄体细胞,各阶段被膜上均存在ghrelin表达,主要为纤维及血管的着色;黄体内ghrelin主要定位于大黄体细胞,另外部分小细胞也有表达,从分布范围和染色强度看,呈现出少-多再渐少的变化趋势;结合各周龄山羊黄体组织中ghrelin阳性产物相对表达量的分析,表明在妊娠早中期,黄体组织内有较高的ghrelin表达,而在妊娠后期表达较低.不同妊娠时期山羊黄体组织中ghrelin的这种周期性表达模式与黄体的功能相适应,提示ghrelin的表达与黄体的功能密切相关.     

牦牛发情周期黄体组织结构的观察

选用48头成年母牦牛，采用光镜和电镜技术对发情周期中不同时期黄体的组织结构进行了观察。结果表明，牦牛黄体主要由2种细胞组成，即颗粒黄体细胞（granulasa lutein cell，GLC）和膜黄体细胞（theca lutein cell，TLC），其特征性变化主要表现在GLC和纤维的分布。成熟黄体中GLC及其胞核的平均直径分别为36．6μm和15．2μm，而TLC则分别为14．4μm和10．9μm。黄体细胞胞质中线粒体的比例随黄体的成熟而增高；脂滴在Ⅰ期黄体时较多，Ⅱ期时减少，Ⅲ期时显著增多，后又减少；滑面内质网也随黄体的成熟而增加，并随黄体的退化发生膨胀。黄体组织中有同心圆状或同心轮状的粗面内质网膜系统。黄体细胞间主要是缝隙连接，偶见中间连接。黄体组织中存在窗孔型毛细血管．     

黄体生理的近代进展

虽然对黄体的发育、维持和退化进行了多年的研究,但对调节孕酮合成和分泌的内分泌及细胞机理仍不清楚。为探明黄体寿命及孕酮合成和分泌相关的机理,本文着重讨论(1)排卵前卵泡诸因子对黄体功能的影响;(2)孕酮合成的激素刺激作用;(3)不同类型黄体细胞对孕酮分泌的影响;(4)分泌粒颗对黄体功能的作用。排卵前卵泡决定着黄体功能猪、牛、绵羊的黄体是由颗粒细胞和膜     

涉及溶黄体的细胞成分

家畜黄体的退化取决于子宫释放的PGF2α。尽管PGF2α在溶黄体中起主要作用,但人们对PG诱导黄体细胞水平退化的实际机制还知之甚少。迄今许多研究都把焦点集中到PGF2α活动的细胞位置上,而且这种化合物看来似乎对黄体细胞能产生多种效应。大黄体细胞可能最初对溶黄体信号起反应,但退化过程也许需要大小黄体细胞以及黄体细胞和非黄体细胞之间的交流传达。免疫系统似乎有效地包含在溶黄体过程中,因此黄体细胞向某种类型的免疫细胞传递有效的信号是可能的。目前已知黄体细胞可与多种免疫细胞分泌物起反应,这种见解可能会导致涉及黄体退化的其它机制的发现。     

长大杂母猪黄体细胞的分离和培养

黄体的主要功能是分泌孕酮,为动物妊娠所必需。尤其对于猪,黄体是整个妊娠期孕酮的惟一来源,猪的整个妊娠期都需要有黄体的支持。妊娠期间任何时候黄体功能被破坏,都会在24～36h内导致流产[1]。笔者在查阅文献时,罕见对猪黄体细胞的研究报道,故笔者参照相关文献方法[2～9],探索了长大杂母猪黄体细胞的分离和培养方法。1材料与方法1.1样品来源所用黄体均采自附近屠宰场4～6月龄健康长大杂母猪。1.2仪器CO2培养箱;超净工作台;电子天平;电热恒温水槽;台式离心机;倒置显微镜;压力灭菌消毒器。1.3试剂胶原酶,胎牛血清,M199培养干粉,台盼蓝,HEP…     

前列腺素D2对山羊黄体细胞内分泌功能及其凋亡相关基因表达的影响

旨在研究前列腺素家族中生殖领域鲜有报道的PGD₂成员对单一环境下黄体细胞内分泌功能及其凋亡相关基因表达的影响，并解析其在黄体退化中的作用机理，为全面探析前列腺素家族成员的生物学作用提供新的理论依据。采集空怀母山羊黄体中期的卵巢组织，通过胶原酶II消化和胰酶差速离心法分离纯化以获得山羊黄体细胞。采用DMEM/F12进行离体培养，观察不同离体培养时间的黄体细胞生长状态；采用免疫组化法和细胞形态特征鉴定黄体细胞，将PGD₂设置三个不同梯度确定其对黄体细胞作用效果的剂量依赖性关系。最后，通过PGD₂最佳依赖性剂量处理黄体细胞，利用ELISA法检测黄体细胞的内分泌功能变化，流式细胞术测定黄体细胞的凋亡率及qRT-PCR/Western blot法检测凋亡相关基因mRNA/蛋白表达水平。结果显示，经突触素(synaptophysin, SYP)特异性表达蛋白鉴定，成功分离并获得了山羊原代黄体细胞。细胞形态实时观察和ELISA检测结果显示，离体培养5 d时黄体细胞胞质饱满、外形紧凑、形态清晰可见，并且黄体细胞的内分泌P₄     

母牛持久黄体的诊断与治疗

母牛黄体在超过正常时限而仍然存在且保持正常功能者,称为持久黄体。这种黄体的组织结构和功能与妊娠黄体或发情周期黄体没有区别,同样可以分泌孕酮,抑制卵泡发育,使发情周期停止循环,引起不育。此病多见于母牛,而且多数继发于某些子宫疾病,原发性的持久黄体在子宫处于正常未孕状态的牛及其他家畜均比较少见。囊肿黄体演变成持久黄体的极其稀少,妊娠黄体一般在产后7天之内完全退化,大多数不会转变为持久黄体。     

Effect of homogenized embryos on IUD-induced luteal regression in the ewe

The effect of homogenized embryos on IUD-induced luteal regression in the ewe was studied. Plastic spiral IUDs were inserted in an uterine horn adjacent to an ovary containing a corpus luteum during various times of the estrous cycle. The ewes were sacrificed on Day 6 for examination of the corpus luteum. Estrous Cycle Day 3 was the last day in which the IUD insertion induced luteal regression. Corpus luteum was maintained in ewes when the IUD was inserted on Day 4, 5, or 6. Corpus luteum regression was not prevented when homogenized 14- or 15-day-old embryos were injected into the uterus at the time of IUD insertion. Ewes which received an IUD, a cannula, and an infusion of saline or homogenized embryos on Days 3, 4, and 5 maintained corpora lutea in 4 of 7 embryo-infused ewes and in none of 7 saline-infused ewes (p less than .05). It was determined that the IUD must remain in the uterine horn for longer than 1 day to induce corpus luteum regression and that embryos can sometimes prevent the IUD-induced regression.     

Reproductive Biology of Chamaeleo Pumilus Pumilus with Special Reference to the Role of the Corpus Luteum and Progesterone

The morphology of the female reproductive tract and of the ovaries of the ovoviviparous C. pumilus was studied. Sperm storage organs were found in the vaginal region and changes in the histological appearance of the corpus luteum indicated a cyclic function similar to that found in mammals. Studies with ¹⁴C labelled leucine suggested that amino acid transfer occurred between the mother and the embryos. A radio-immuno assay of the progesterone content of the corpus luteum showed that the corpus luteum contains 56,8 μg progesterone/g of fresh luteal tissue and that the mean plasma levels of progesterone increased from 945,6 pg/ml in non-gravid to 2296,0 pg/ml in gravid females. There also appears to be a post-ovulatory surge of progesterone (4946,0 pg/ml). Oestrogens were found to stimulate the oviducal mucosa while progesterone acted synergjstically with oestrogen. Oestrogens also stimulated the production of serum protein fractions. Progesterone caused yolk regression and thus prevented the onset of the next follicular phase. Studies involving ovariectomy and progesterone replacement, indicated that progesterone and the corpus luteum are essential for the maintenance of gestation. It was concluded that several features of the reproductive biology of C. pumilus can be considered to be distinctly mammalian and that these features are of considerable evolutionary importance.     

VEGF在家畜黄体早期发育过程中对血管生成的调控作用

对黄体时期VEGF依赖性血管生成的分子机制研究，将有助于我们开发新的策略用于治疗黄体相关的不孕症，以及改善动物的繁殖性能。论文对VEGF在家畜黄体血管生成过程中的调控作用进行综述，旨在为临床研究及畜牧生产提供理论依据及参考资料。     

Morphological study of the corpus luteum in the rat

The cyclic related growth and regression of the corpus luteum during four consecutive oestrous cycles of the regular four-day-cycling (ie, 16 days), virgin albino Wistar rat were followed up by light and electron microscopic investigation of the ovaries. After ovulation, follicular granulosa cells differentiated into luteal cells in the newly formed corpus luteum. Based on their specific histological characteristics, four various types of corpus luteum in each stage of the oestrous cycle could be identified. As soon as the luteal cells started to degenerate, the number of fibroblasts progressively increased and apoptotic degeneration of luteal cells was initiated and became most prominent during oestrus. Complete regression of the corpus luteum was seen after 15 days. This study shows a strictly organised pattern of luteal cell growth and degeneration in the corpus luteum of the regular four-day-cycling, virgin Wistar rat. The morphological alterations may be regulated by a hormonal fluctuation.     

Prolonged luteal activity in mares--a semantic quagmire

Prolonged luteal activity is one of the most formidable terminology challenges in mare reproductive biology. Prolonged luteal activity can be a result of persistence of an individual corpus luteum or the sequential development of luteal glands, each of which may have a normal life span. Luteal tissue can originate from an unovulated follicle or from an ovulation occurring during either follicular or luteal dominance. These complexities, together with ambiguous and inconsistent terminology, have resulted in confusion regarding those conditions which can be grouped broadly under the term prolonged luteal activity. Persistence of an individual corpus luteum can occur in association with severe damage to the endometrium resulting in loss of the uterine luteolytic mechanism. Spontaneous (no known uterine pathology) persistence of the corpus luteum from the follicular-phase ovulation has not been documented adequately as a clinical entity. The occurrence of ovulation towards the end of dioestrus may cause confusion about the origin of prolonged luteal activity. Such immature dioestrous corpora lutea may not respond to the release of uterine luteolysin, thereby leading to prolonged luteal activity even though the original corpus luteum regressed at the normal time. In the absence of critical monitoring of the corpus luteum (eg by ultrasound) the prolonged activity could be attributed erroneously to persistence of the corpus luteum from the follicular-phase ovulation. Pseudopregnancy is another confusing term that is sometimes used to describe persistence of the corpus luteum, especially when the luteal persistence is caused by embryonic loss after the embryo has blocked the uterine luteolytic mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lectinhistochemical and cytometrical evaluation of the corpus luteum of the rat at the end of pregnancy

Most studies on the biochemistry and structure of the corpus luteum have focused on elucidating the processes of progesterone synthesis and release. In the present work, the histochemical composition of the corpus luteum of the rat was evaluated using lectinhistochemistry on rats at the end of pregnancy (days 18-23). We also analysed the morphology of the luteal cells, to characterize the changes attributable to regression in this organ. Seven biotinylated lectins were used (CON-A, WGA, DBA, SBA, PNA, RCA and UEA-I) following pre-set protocols (ABC method). The average diameter and area of the cells and their nuclei were measured. High reactivity of the luteal cells was observed with CON-A and a lower reactivity with WGA. The capillary endothelium gave positive reactivity with WGA and to a certain extent with SBA, PNA and RCA. Vesicular structures were intensely stained with DBA, and were more abundant in sections from animals with more advanced pregnancy, which could be attributable to cellular debris, on the basis of their morphologic characteristics. There were no significant differences among the cytometric variables analysed in comparisons of the values corresponding to the different days of gestation. These observations, together with previous research, suggest that, on the day of delivery, the corpus luteum of the rat is in the very early stages of structural regression, with no changes at the morphological level, but with changes at the molecular level.     

Angiogenesis and Interstitial Pressure in a Rat Tumour Model

Introduction and Aim:  The corpus luteum is one of the most intensely vascularized tissues. Luteal angiogenesis is strictly controlled and blood vessels regress completely within a short period of time. The aim of this study was to investigate vascular dynamics in relation to cellular and molecular mechanisms of luteal angiogenesis and anti-angiogenesis.
Material and Methods:  Endothelial cells of blood vessels in paraffin sections of bovine corpora lutea from different stages were examined by labelling with the lectin Bandeiraea simplicifolia agglutinin I. Angiogenesis was studied by morphometry of the capillaries, and immunolocalization of the angiogenic factor VEGF and VEGF-receptor 2. Presence of apoptotic luteal and endothelial cells was investigated using the TUNEL test and transmission electron microscopy.
Results:  During development of the corpus luteum (day 3–8 of the oestrous cycle) a dense capillary network (8–12% area ratio) is established and maintained until day 17. Early regression (day 18–24) is characterized by a remarkable decrease of capillaries (1% area ratio). In the regressing corpus luteum the number of apoptotic luteal cells is closely correlated ( r  = 0.9) to the number of apoptotic endothelial cells. VEGF is immunolocalized in luteal cells (day 3–17), smooth muscle cells and endothelial cells of arterioles of the regressing corpus luteum. During late luteal regression, a moderate increase of capillaries (2.5% area ratio) is obvious.
Conclusions:  The dynamic changes of the capillarity during development and regression of the cyclic corpus luteum correlate with VEGF and VEGF-R2 activities. In contrary to expectations the late stage of luteal regression is accompanied by angiogenesis. One reason for this phenomenon may be an increase in metabolic activity resulting in re-organization of blood vessels already regressed.     

藏绵羊卵巢组织学及卵泡超微形态的观察

旨在通过观察藏绵羊卵泡、黄体的组织学特征及卵泡的超微形态,探讨其与生理功能的关系.本研究运用大体解剖、常规组织切片和H.E染色及透射电镜技术对藏绵羊卵巢卵泡和黄体的组织结构特点以及卵泡的超微形态进行观察和分析.结果发现,藏绵羊黄体期和卵泡期卵巢的宽度和厚度存在显著差异(P＜0.05),而重量和长度无显著差异(P＞0.0...     

Immunohistochemical localization of steroidogenic enzymes and prolactin receptors in the corpus luteum and placenta of spotted seals (Phoca largha) during late pregnancy

To study luteal function in the late gestational period of Phocidae (seals), we analyzed the localization of steroidogenic enzymes (P450scc, 3betaHSD and P450arom) and prolactin receptors in the corpora lutea of pregnant spotted seals (Larga seal; Phoca largha) immunohistochemically. P450scc, 3betaHSD and prolactin receptors were present in all luteal cells of each corpus luteum, and most luteal cells were immunostained for P450arom. Although we analyzed only two specimens, P450scc, 3betaHSD and prolactin receptors were negatively immunostained in the placentae. P450arom was present in the syncytiotrophoblast of placentae. These findings suggest that 1) the corpus luteum of the spotted seal synthesizes pregnenolone, progesterone and estrogen during late gestational period, 2) the placenta of this species do not possess the capacity to synthesize progesterone, and 3) like other terrestrial carnivores, this species requires prolactin to maintain the corpus luteum during pregnancy. These characteristics support the recent classification of family Phocidae in the order Carnivora, and suggest a relationship between prolactin and reproductive failure during the post-implantation period in pinnipeds.     

Angiogenesis and Vascular Regression in the Corpus Luteum Periodicum

Introduction and Aim: The corpus luteum is one of the most intensely vascularized tissues. Luteal angiogenesis is strictly controlled and blood vessels regress completely within a short period of time. The aim of this study was to investigate vascular dynamics in relation to cellular and molecular mechanisms of luteal angiogenesis and anti‐angiogenesis. Material and Methods: Endothelial cells of blood vessels in paraffin sections of bovine corpora lutea from different stages were examined by labelling with the lectin Bandeiraea simplicifolia agglutinin I. Angiogenesis was studied by morphometry of the capillaries, and immunolocalization of the angiogenic factor VEGF and VEGF‐receptor 2. Presence of apoptotic luteal and endothelial cells was investigated using the TUNEL test and transmission electron microscopy. Results: During development of the corpus luteum (day 3–8 of the oestrous cycle) a dense capillary network (8–12% area ratio) is established and maintained until day 17. Early regression (day 18–24) is characterized by a remarkable decrease of capillaries (1% area ratio). In the regressing corpus luteum the number of apoptotic luteal cells is closely correlated (r = 0.9) to the number of apoptotic endothelial cells. VEGF is immunolocalized in luteal cells (day 3–17), smooth muscle cells and endothelial cells of arterioles of the regressing corpus luteum. During late luteal regression, a moderate increase of capillaries (2.5% area ratio) is obvious. Conclusions: The dynamic changes of the capillarity during development and regression of the cyclic corpus luteum correlate with VEGF and VEGF‐R2 activities. In contrary to expectations the late stage of luteal regression is accompanied by angiogenesis. One reason for this phenomenon may be an increase in metabolic activity resulting in re‐organization of blood vessels already regressed.