Analysis of TNF-α and IL-1β expression by enzyme-linked immunosorbent assay (ELISA)

The right hemisphere of the brain was dissected from rats at 0, 6, 24, and 48 h and immediately weighed. The tissue was frozen in 1 ml PBS (pH 7.4) and homogenized, centrifuged at 12 000×g at 4°C for 20 min. The protein levels of TNF-α and IL-1β were determined using ELISA kits for TNF-α (Immuno-Biological Laboratories, Hamburg, Germany; cat. no. JP27194) and IL-1β (Immuno-Biological Laboratories, Minneapolis, MN, USA; cat. no. 27193) according to the manufacturers’ protocols. Absorbance at 450 nm was measured within 30 min using an ELISA microplate reader.