A qualitative analysis of glycosaminoglycans in the reproductive tract of mares

Abstract

A compositional analysis of glycosaminoglycans (GAGS) in the reproductive tract of mares was performed. Uteri, ovaries and oviducts were obtained at a slaughter house, and stage of estrous cycle was estimated. Follicular fluid was aspirated from follicles of various sizes (1-5, 6-10, 11-20, 21-30 or 31-40 n-d). Lumina of oviducts and uterine horns were flushed. In addition, oviductal epithelial cells were obtained for culture. Follicular fluid, oviductal and uterine horn flushes, and cell-conditioned media were analyzed for GAGS. Samples were also purified by chromatography. Quantity of total GAGs was estimated using a calorimetric assay. Compositional analysis of GAGs was performed using an electrophoretic assay in pyridine/fonnic acid or barium acetate. Total glycosaminoglycan (GAG) quantity and concentration in follicular fluid was affected by follicular size (P < 0.05). Total GAG concentration in follicular fluid decreased with increasing follicular size. Total quantity of GAGS, however, increased with follicular size. The stage of the estrous cycle did not affect concentration or quantity of GAGs (P > 0.05). Chondroitin sulfate A and C (CSA-CSC) were the predominant GAGs found in follicular fluid (average of 73%), followed by chondroitin sulfate B and hyaluronic acid (CSB-1h; average of 17%), and heparin (BEP; average 10%). The relationship between concentration of total GAGs and follicular size was represented by a quadratic regression model (r = -0.87, P = 0.0001). In addition, concentration of CSA-CSC (r = -0.91, P = 0.0001), CSB-HA (r = -0.61, P = 0.0020), and HEP (r = - 0.59, P = 0.0030) were negatively correlated with follicular size. The electrophoretic procedure did not permit adequate separation among GAGs recovered from oviductal and uterine horn flushes. Production of GAGs by oviductal epithelial cells in vitro was insufficient for quantification or qualitative analysis. The predominant GAGs in the follicular fluid of mares may differ from previous studies in other species.