Berisha Bajram, Steffl Martin, Welter Harald, Kliem Heike, Meyer Heinrich H D, Schams Dieter, Amselgruber Werner
Physiology Weihenstephan, Technical University of Munich, Weihenstephaner Berg 3, 85354 Freising, Germany.
Reprod Fertil Dev. 2008;20(2):258-68. doi: 10.1071/rd07125.
The aim of the present study was to evaluate the pattern of regulation of vascular endothelial growth factor (VEGF)-A (isoforms 121, 165, 189), VEGF receptor tyrosine kinases (VEGF-R1 and VEGF-R2), matrix metalloproteinase (MMP)-1, MMP-2, MMP-14, MMP-19, tissue-specific inhibitor of metalloproteinases (TIMP)-1, TIMP-2, tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), urokinase plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1) in time-defined follicle classes before (0 h) and after the application of gonadotrophin-releasing hormone (GnRH). Bovine ovaries containing periovulatory follicles or new corpora lutea (CL; Days 1-2) were collected 0, 4, 10, 20 and 25 h (follicles) or 60 h (CL) after the injection of GnRH. Transcripts of VEGF isoforms (VEGF(121), VEGF(165), VEGF(189)) were upregulated 4 h after GnRH injection (during the luteinising hormone (LH) surge) and decreased thereafter to lowest levels around ovulation. All VEGF isoforms and their receptors were upregulated again after ovulation. The VEGF peptide concentration in follicular fluid decreased 20 h after GnRH injection, followed by an increase in follicles 25 h after GnRH. Expression of MMP-1 mRNA increased rapidly 4 h after GnRH injection and remained high during the entire experimental period. In contrast, MMP-19 mRNA increased significantly only after ovulation. Expression of TIMP-1 mRNA increased 4 h after GnRH and again after ovulation. Expression of tPA mRNA increased 4 h after GnRH and remained high during the entire experimental period, whereas expression of uPA transcripts increased significantly only after ovulation. Both uPAR and PAI-1 mRNA levels increased in follicles 4 h after GnRH and again after ovulation. The amount of MMP-1 protein (immunolocalisation) increased in follicles 10 h after GnRH: additional staining was observed in the granulosa cell layer. In conclusion, the temporal and spatial pattern of regulation of VEGF and extracellular matrix-degrading proteinases during periovulation suggests they are important mediators of the LH-dependent rupture of bovine follicles and for early CL formation (angiogenesis).
本研究的目的是评估在应用促性腺激素释放激素（GnRH）之前（0小时）和之后，在特定时间的卵泡类别中血管内皮生长因子（VEGF）-A（亚型121、165、189）、VEGF受体酪氨酸激酶（VEGF-R1和VEGF-R2）、基质金属蛋白酶（MMP）-1、MMP-2、MMP-14、MMP-19、金属蛋白酶组织特异性抑制剂（TIMP）-1、TIMP-2、组织型纤溶酶原激活剂（tPA）、尿激酶型纤溶酶原激活剂（uPA）、尿激酶型纤溶酶原激活剂受体（uPAR）和纤溶酶原激活剂抑制剂-1（PAI-1）的调控模式。在注射GnRH后的0、4、10、20和25小时（卵泡）或60小时（黄体）收集含有排卵前卵泡或新黄体（CL；第1 - 2天）的牛卵巢。GnRH注射后4小时（在促黄体生成素（LH）峰期间）VEGF亚型（VEGF(121)、VEGF(165)、VEGF(189)）的转录本上调，此后下降至排卵前后的最低水平。排卵后所有VEGF亚型及其受体再次上调。卵泡液中的VEGF肽浓度在GnRH注射后20小时下降，随后在GnRH注射后25小时卵泡中增加。GnRH注射后4小时MMP-1 mRNA的表达迅速增加，并在整个实验期间保持高水平。相比之下，MMP-19 mRNA仅在排卵后显著增加。TIMP-1 mRNA的表达在GnRH注射后4小时增加，排卵后再次增加。tPA mRNA的表达在GnRH注射后4小时增加，并在整个实验期间保持高水平，而uPA转录本的表达仅在排卵后显著增加。GnRH注射后4小时卵泡中uPAR和PAI-1 mRNA水平均增加，排卵后再次增加。GnRH注射后10小时卵泡中MMP-1蛋白（免疫定位）的量增加：在颗粒细胞层观察到额外的染色。总之，排卵期间VEGF和细胞外基质降解蛋白酶调控的时间和空间模式表明它们是牛卵泡LH依赖性破裂和早期黄体形成（血管生成）的重要介质。
