Enzyme-linked immunosorbent assay (ELISA)
Serum samples were collected and centrifuged for 10 minutes at 3000g at 4 °C to obtain supernatants. Expressions of IL-6, IL-1β, and TNF-α were determined using commercially available ELISA kits (MDL Biotech, Beijing, China). Concentrations of inflammation factors were tested according to the manufacturer’s instructions and presented as pg/ml of serum protein.