Matrix Metalloproteinases and Tissue Inhibitors of Matrix Metalloproteinases as Plasma Indicators of Bovine Cystic Ovarian Disease

Abstract

Cystic ovarian disease (COD) is one of the main causes of infertility in dairy cattle and has a high economic impact on farmers. COD is caused by an endocrine imbalance within the hypothalamic-pituitary-ovarian axis preventing the mature Graafian follicle from ovulating. The cause at the molecular level is not well understood. However, the matrix metalloproteinases (MMP) and plasminogen activator/plasmin families of extracellular (ECM) matrix-degrading proteinases are involved in Graafian follicle breakdown and oocyte release in the ovulation process. Our research investigated the possibility of using plasma concentrations of MMP-2 and -9 and their natural tissue inhibitors (TIMP) -1 and -2 as prognostic indicators of COD. Plasma samples from cystic and non-cystic dairy cows were analyzed using ELISA. Although plasma concentrations of MMP-2 and -9 were greater and TIMP-2 was lower in non-cystic compared to cystic cows, no significant differences were observed in MMP-2 and -9 and TIMP-1 and -2 due to cyst status. However, the TIMP-1:MMP-9 and TIMP-2:MMP-2 molar ratios were greater, (P = 0.099) and (P = 0.038), respectively, in cystic compared to non-cystic cows, suggesting a proteolytic insufficiency in cows with COD that may be a contributing factor to the anovulatory pathology. These data may provide the groundwork for future research and development of tools for dairy farmers to selectively choose replacement heifers less likely to develop COD.