To study the effects of moxibustion at different time points on serum level of tumor necrosis factor-α (TNF-α) in rats with rheumatoid arthritis (RA), and to explore its regulation mechanism on circadian rhythm.
A total of 96 Sprague-Dawley (SD) adult rats were randomly assigned into a blank group, a model group, a moxibustion at 5-7 AM group and a moxibustion at 5-7 PM group, 24 rats in each group, half male and half female. Each group was further divided into a 0 AM group, a 6 AM group, a 12 N group and a 6 PM group, 6 rats in each group. All rats were treated with the 12 h/12 h light-dark cycle in the whole process of experiment. Except for the blank group, all rats were treated with intracutaneous injection of freund's complete adjuvant (FCA) at right foot pad to establish the RA model. The rats at the two moxibustion groups were treated with grain-sized moxibustion at "Shenshu" (BL 23) and "Zusanli" (ST 36) at 5-7 AM and 5-7 PM, respectively, one side per treatment, once a day; six treatments were taken as one course and 3 courses were given with an interval of one day between courses. The rats in the remaining groups were treated with identical fixation but without moxibustion intervention. The right foot volume was measured before model establishment, after model establishment and after treatment. The blood samples were collected after treatment and the serum level of TNF-α was measured by ELISA. The SPSS 21.0 software and Halberg Cosinor were adopted to analyze the experiment data.
After treatment, compared with the blank group, the foot swelling severity was significantly increased in the model group, moxibustion at 5-7 AM group and moxibustion at 5-7 PM group (all 
Moxibustion could effectively reduce the serum level of TNF-α to relieve the foot swelling severity in RA rats. Moxibustion could regulate the circadian rhythm of TNF-α to play its effects on the inhibition of the synthesis of TNF-α. No efficacy is observed between the treatment at 5-7 AM and 5-7 PM.