Correlation between the dynamics of total antioxidant capacity (TAC) and glutathione peroxidase (GPx) activity and the sizes of bovine antral follicles and follicle dominance

Abstract

Total antioxidant capacity (TAC) is comprised of enzymatic and non-enzymatic antioxidants, which are essential to the ability of cells to cope with the oxidative stress generated during follicular growth and maturation. Through its direct and indirect actions, it is likely that glutathione peroxidase (GPx) plays a pivotal role in providing antioxidant protection to follicles. The objective of our study was to estimate the levels of TAC and GPx in follicular fluid that originated from antral follicles of small (<6 mm), medium (6–8 mm), and large (>8 mm) sizes. These levels were then correlated with follicle size and follicle dominance. Prospective study. Bovine ovaries were collected from the slaughterhouse (Champlain Beef Co., Whitehall, NY) within 30 minutes of death of the animal and placed in room temperature saline solution with antibiotic. These samples were obtained from naturally cycling cows (11/2–3 yrs). The follicular fluid was collected from antral follicles of different sizes ranging from 2–25 mm. Each fluid sample was spun (7000 g for 3 min) to remove all cell contaminants, aliquoted, and frozen at − 80°C. After processing of the follicular fluid, the antioxidants TAC and GPx were measured using assay kits based on chemiluminescence methods. The average TAC level was 1.04 ± 0.58 AntiOx mM and the GPx activity was 0.20 ± 0.11 nmol/min/mL respectively. There was no significant correlation in the levels of TAC and GPx activity with either follicle size or follicle dominance. The plots below show the activities of the 2 markers assayed with the categorical ordinals. Our study found no significant trends in the TAC capacity and GPx activity of bovine antral follicles with increasing follicle size or follicle dominance. Future studies with larger sample sizes are needed to assess potential dynamic trends in TAC and GPx activity.