Porcine Follicular Fluid CCL2 Levels

Ovary pairs from prepubertal three-way cross pigs (mixed Yorkshire, Landrace, and Duroc breeds) obtained from a local slaughterhouse, were collected for follicular fluid analysis. Aspirated porcine follicles were divided into three groups: small (1–2 mm), medium (3–7 mm), and large (≥8 mm) (29 (link), 30 (link)). To eliminate debris and blood, the pFF was centrifuged for 20 min at 94 g and 4°C. The supernatant was extracted using a 10 cc disposable syringe (Sofjec; Hwajin Medical, Chungnam, Korea) with a 0.2 μm syringe filter (Corning, NY, USA) and frozen at −80°C. A porcine CCL2/MCP-1 ELISA kit (ES2RB; Invitrogen, Carlsbad, CA, USA) was used to measure the CCL2 concentration in the pFF samples, according to the manufacturer's instructions. The CCL2 concentration was determined using the mean value of four ELISA experiments, performed in duplicates.