Interventional effects of triptolide on the levels of cytokines in peripheral serum and articular cavity of rats with collagen induced arthritis

Shenghao TU; Dongyun SHENG; Yonghong HU; Keqin ZENG

ABSTRACT

BACKGROUND:

Common threewingnut root has the functions of anti-inflammation and immune inhibition, etc., and it has been used at present to treat various autoimmune diseases including rheumatoid arthritis.. Common threewingnut root has complex components, and triptolide is acknowledged as one of the important effective components of common threewingnut root.

OBJECTIVE:

To establish rat models of type Ⅱ collagen induced arthritis, and observe the effects of triptolide on the contents of interleukin-6,interleukin-10 and tumor necrosis factor alpha (TNF-α) in peripheral serum and synovial fluid.

DESIGN:

A randomized control animal experiment.

SETTING:

Department of Integrated Traditional and Western Medicine,Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology.MATERIALS The experiments were carried out in the Tongji Hospital from November 2004 to July 2005. Fifty healthy male Wistar rats of clean degree were purchased from the experimental animal center of Tongji Medical College, Huazhong University of Science and Technology [qualification number of animal [scxk(E)2004-2007]. Triptolide (nobatch number because of temporary production) was bought from Fujian Institute of Medical Sciences, and the purity was above 98.5%.

METHODS:

① Ten of the 50 rats were randomly selected as the normal controls, and the others were made into models. Type Ⅱ collagen emulsion was injected intradermally at five points along the back and tail of the rats,0.05 mL for each point, and injected intradermally at two points after 15 days. The rats in the normal control group were treated with saline in the same way. The effects of the model establishment were evaluated according to the scoring standards of arthritis index at 30 days after the first immunity, and the rats scored 6 points or above were taken as successful models and enrolled in the experiments. Twenty successful rat models were randomly divided into arthritis model group (n=10) and triptolide treated group (n=10). ② Triptolide (100 mg/L)was dispensed into parenteral solution with propylene glycol (0.05 in volume fraction), and then intramuscularly injected into hindlimb of rats in the triptolide treated group (0.04 mL/100 g), once every three days for 30 days. The rats in the normal control group were given isovolume saline, and those in the arthritis model group were treated with isovolume propylene glycol (0.05 in volume fraction). ③ The materials were removed at 30 days after administration. The contents of interleukin-6, interleukin-10 and TNF-α in peripheral serum and synovial fluid were detected with enzyme-linked immunosorbant assay(ELISA).MAIN OUTCOME

MEASURES:

The effects of triptolide on contents of TNF-α, interleukin-6 and interleukin-10 in peripheral serum and synovial fluid were observed.

RESULTS:

Fifty male Wistar rats of clean degree were selected, 10 were used as normal controls, and 20 of the other 40 rats were successfully made isto models and enrolled in the analysis of results. ① The TNF-α contents in peripheral serum and synovial fluid were the highest in the arthritis model group, and obviously decreased after treatment of triptolide [(35.09±8.82), (15.35±3.56) ng/L; (44.17±8.94), (22.54±4.76) ng/L; P＜ 0.01], which were similar to those in the normal control group (P ＞ 0.05).② The contents of interleukin-6 in peripheral serum and synovial fluid were the highest in the arthritis model group, and were obviously decreased after treatment of triptolide [(76.58 ±6.81), (42.45 ±5.72) rig/L;(88.69±10.56), (48.67±5.97) ng/L; P ＜ 0.01], but did not recover to the levels in the normal control group (P ＜ 0.05). ③ The contents of interleukin-10 in peripheral serum and synovial fluid were the lowest in the arthritis model group, and obviously increased after treatment of triptolide[(17.53±2.07), (21.23±2.91) ng/L; (10.59±2.96), (14.74±1.85) ng/L; P＜ 0.01], which were similar to those in the normal control group (P ＞ 0.05).

CONCLUSION:

Triptolide can treat arthritis by modulating the contents of cytokines.