Levels of TNF-α in hindpaw after intraplantar CFA injection. Seventy-two hours after CFA injection, tissues from both hindpaw were collected and analyzed immediately by TNF-α EIA kit. Control (contra): contralateral to CFA, non-injected. CFA (ipsi): injected. Data are expressed as mean ± SEM and were analyzed using an un-paired Student's t-test. ***p < 0.001; compared to control (SD rats, N = 7 per group).