Secretion of matrix metalloproteinases 2 and 9 and tissue inhibitor of metalloproteinases into follicular fluid during follicle development in equine ovaries

Abstract

Extensive tissue remodelling is required in equine ovaries for follicle growth and development and also migration of the follicle to the ovulatory fossa, where ovulation occurs. The mechanisms for these processes are largely unexplored. Matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors (TIMPs) are important for control of breakdown of extracellular matrix during tissue remodelling. The aims of this study were to determine the pattern and sites of secretion of the gelatinases MMP-2 and -9 and TIMPs into follicular fluid during follicle development in mare ovaries. The predominant gelatinase detected in follicular fluid was MMP-2, which was present in similar amounts throughout follicular development, as demonstrated by zymography. MMP-9 was also present in follicular fluid and secretion increased significantly (P < 0.05) with development of follicles from < 10 mm to 11-20 mm in diameter. Follicular fluid also contained TIMP-1, TIMP-2, unglycosylated and glycosylated TIMP-3, and TIMP-4, as shown by reverse zymography. The abundance of TIMPs remained largely unchanged during follicle development. MMP-2 and -9 were localized by immunohistochemistry to stromal cells and granulosa and theca cells. TIMP-1, -2, -3 and -4 were present in granulosa and theca cells of the follicle and in stromal cells and also associated with extracellular matrix of the ovarian stromal tissue. The MMPs and TIMPs are likely to be involved in the regulation of the breakdown of extracellular matrix during tissue remodelling for follicle development and migration to the ovulation fossa in mares.

Do follicular fluid gelatinase levels affect fertilization rates and oocyte quality?

“…Bagavandoss et al [17] reported that the presence of MMP-2 in the neonatal ovary suggests that it functions in follicular development. Although MMP-9 levels increase when follicle diameter increases, MMP-2 levels are similar at all stages of follicular development [18]. Imai et al [19] suggested that MMP-2 activity, in particular, in follicular fluid could serve as a marker of follicular health, whereas an abundance of pro-MMP-9 could possibly denote a follicular cyst.…”

Glucocorticoid receptor-mediated regulation of MMP9 gene expression in human ovarian surface epithelial cells

“…Portions (10 mL) of concentrate were electrophoresed under native, nondenaturing conditions on a 7.5% polyacrylamide gel containing 10% gelatin as substrate. Zymographic analysis was then carried out by previously published methods (15). Intensity of digested bands was quantified using Open lab image analysis software (Improvision, Coventry, United kingdom) after densitometric scanning (BioRad Laboratories Ltd., Hemel Hempstead, United Kingdom).…”

Proteolytic Mechanisms in the Ovulatory Folliculo-Luteal Transformation

“…Matrix metalloproteinase-9 was elevated in fluid of preovulatory follicles of pigs [95] and horses [96] and in formative corpora lutea or luteinized granulosa cells of rats [97], cattle [98,99], and human beings [100]. Collagenase-3 (MMP-13), which degrades collagens I-III, was increased in preovulatory rat follicles [101,102].…”