Dhar A, Salamonsen L A, Doughton B W, Brown R W, Findlay J K
Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia.
J Reprod Fertil. 1998 Sep;114(1):147-55. doi: 10.1530/jrf.0.1140147.
Ewes actively immunized against alpha N, the N-terminal peptide of inhibin alpha 43 precursor, have lowered fertility associated with ovulation failure, restricted tissue remodelling and reduced matrix metalloproteinase-2 activity in the follicular fluid at the time of expected ovulation. This could be due to altered ratios of matrix metalloproteinase-2 and tissue inhibitor of matrix metalloproteinase (TIMP-1), or to the onset of atresia in antral follicles destined to ovulate. The objectives of the present study were to investigate the effects of immunization against alpha N on the localization of TIMP-1 in ovine follicles, and on follicular growth and atresia in the follicular phase. Ewes were either immunized against alpha N or remained as controls and the ovaries were removed before (0, n = 4) and at 12 h (n = 4) and 24 h (n = 4) after hCG administration in a synchronized follicular phase, 48 h after removal of intravaginal pessaries. Observations were made on a single section taken through the largest follicle present in the ovaries of each ewe. There were no healthy antral follicles > 1 mm in immunized ovaries (0/29) compared with controls (16/31) (P < 0.001), whereas the proportion of healthy antral follicles < 1 mm was the same in each group (9/19 versus 5/12). TIMP-1 immunoactivity was localized in large luteal cells, smooth muscle and endothelial cells, and in all antral follicles, including oocytes. At the time of hCG administration, no TIMP-1 immunoreactivity was detected in the apical region of the follicular wall of large follicles (> 6 mm) compared with the rest of the follicle wall, but staining appeared in the apical granulosa layer 24 h later. In newly formed corpora lutea, TIMP-1 expression was found along the invaginating vascular layer. There was no effect of immunization on the patterns of TIMP-1 immunoreactivity, suggesting that changes in TIMP-1 are not involved in the effects of alpha N. These data are consistent with a paracrine role for alpha N in the selection and atresia of antral follicles, and for TIMP-1 in tissue reorganization and steroidogenesis at the time of ovulation.
用抑制素α43前体的N端肽αN对母羊进行主动免疫后，母羊的生育力降低，这与排卵失败、组织重塑受限以及预期排卵时卵泡液中基质金属蛋白酶-2活性降低有关。这可能是由于基质金属蛋白酶-2与基质金属蛋白酶组织抑制剂（TIMP-1）的比例改变，或者是由于注定要排卵的窦状卵泡闭锁的开始。本研究的目的是调查针对αN免疫对绵羊卵泡中TIMP-1定位以及卵泡期卵泡生长和闭锁的影响。母羊要么用αN免疫，要么作为对照，在同步卵泡期给予hCG之前（0小时，n = 4）、12小时（n = 4）和24小时（n = 4），取出阴道内子宫托48小时后，取出卵巢。对每只母羊卵巢中最大的卵泡取单张切片进行观察。与对照组（16/31）相比，免疫组卵巢中直径大于1mm的健康窦状卵泡数量为0/29（P < 0.001），而每组中直径小于1mm的健康窦状卵泡比例相同（9/19对5/12）。TIMP-1免疫活性定位于大黄体细胞、平滑肌和内皮细胞以及所有窦状卵泡，包括卵母细胞。在给予hCG时，与卵泡壁的其余部分相比，在大卵泡（> 6mm）的卵泡壁顶端区域未检测到TIMP-1免疫反应性，但在24小时后顶端颗粒层出现染色。在新形成的黄体中，TIMP-1表达沿内陷的血管层出现。免疫对TIMP-1免疫反应性模式没有影响，表明TIMP-1的变化不参与αN的作用。这些数据与αN在窦状卵泡的选择和闭锁中的旁分泌作用以及TIMP-1在排卵时组织重组和类固醇生成中的旁分泌作用一致。
