To observe the effect of chronological moxibustion on plasma corticosterone (CORT), corticotrophin releasing factor (CRF) and adrenocorticotropic hormone (ACTH) levels in rheumatoid arthritis (RA) rats, so as to explore its mechanisms underlying improvement of RA.
A total of 144 SD rats were randomly divided into normal control, model, moxibustion, sham-adrenalectomy (ADX, sham-ADX), ADX and ADX+moxibustion groups which were further separately divided into 4 subgroups (4 time-points: 12 pm, 6 am, 12 am, 6 pm, n = 6/subgroup). The RA model was established by subcutaneous injection of Freund's complete adjuvant (FCA, 0. 1 mL) into the right footpad (for rats of the latter 5 groups). In rats of the ADX and ADX+ moxibustion groups, bilateral adrenal glands were removed under anesthesia. Moxibustion was applied to unilateral "Shenshu" (BL 23) and "Zusanli" (ST 36) for 10 min, once daily for 6 days in a week, and continuously for 3 weeks. The paw swelling volume was measured and plasma CORT, ACTH and CRF contents were assayed by ELISA and the circadian rhythm was analyzed by cosine curve fitting (cosinor) method.
The paw swelling volume was significantly increased in the model group than in the normal control group (P<0.05), and decreased remarkably in the moxibustion group (P<0.05). The paw volume was markedly increased in the ADX +moxibustion group in comparison with the moxibustion group (P<0.05). In intact rats, plasma CRF and ACTH contents were significantly increased (P<0.05), and plasma CORT was obviously decreased in the model group (P<0.05). After moxibustion, the increased plasma CRF and ACTH contents and the decreased plasma CORT level Nere considerably reversed (P<0.05). In ADX rats, plasma ORE, ACTH and CORT contents of ADX and ADX + moxibustion groups had no significant.changes compared with the sham-ADX group (P>0.05). Results of the cosine curve fitting analysis showed that the peak phases of plasma CORT contents were -355.78 degrees at about 23:43 in the normal control group, -309.05 degrees at about 20:36 in the model group, -326.5 degrees at about 21:46 in the moxibustion group, -291.65 degrees at about 19:27 in the ADX group and -300.87 degrees at about 20:31 in the ADX + moxibustion group. The peak phases of plasma ACTH contents were -324.08 degrees at about 21:37 in the normal control group, -295.39 degrees at about 19:41 in the model group, -310.81 degrees at about 20:43 in the moxibustion group, -146.51 degrees at about 9:46 in the ADX group and -267.64 degrees at about 17:50 in the ADX+ moxibustion group. The peak phases of plasma CRF contents were -257.47 degrees at about 17:10 in the normal control group, -184.74 degrees at about 12:19 in the model group, -263.00 degrees at about 17:32 in the moxibustion group, -202.46 degrees at about 13:30 in the ADX group and -232.84 degrees at about 15:31 in the ADX+ moxibustion group. It suggests that in the intact RA rats, moxibustion intervention may inhibit modeling-induced decrease of the circadian rhythm of plasma CORT, and hyperactivity of ACTH and CRF circadian rhythm.
VAoxibustion intervention can relieve paw swelling in RA rats and modulate the circadian rhythm activities of plasma CORT, ACTH and ORE levels (HPA axis activities) in intact animals.