The expression of TNF-α and IL-1β at three days after crush injury. At three days after crush injury, specimens of the crushed sciatic nerve were taken at 5 mm distal to the injury site from both sem (p38+/−) and wt (p38+/+) mice. Each section was processed for immunostaining using anti TNF-α antibody, and anti-IL-1β antibody. Scale bar indicates 50 μm. The ratio of the immunopositive area of (a) TNF-α and (b) IL-1β to the total area of the field was calculated as the immunopositive rate, respectively. Asterisks indicate significant difference between genotypes (**P <0.01).