OBJECTIVETo explore the protective mechanism of Fengshiqing Recipe (FR) against bone destruction in collagen-induced arthritis (CIA) rats.

METHODSRats were divided into four groups in the experiment,i.e., the blank control group, the model group, the MTX group (MTX, 1 mg/1 000 g), and the FR group (24 g crude FR/kg). The CIA model was prepared except the blank control group. Medication was started in the MTX group and the FR group from the 14th day after modeling to the 56th day. The toe volume was measured on every Tuesday and Friday. Expression levels of serum IL-17, RANKL, MIP-1alpha were detected after 3-and 6-week intervention. The bone scintigraphy with nuclide (SPECT), bone mineral density (BMD), and the pathological section were observed to assess the intervention of drugs of heat clearing blood activating actions in the bone destruction of CIA rats.

RESULTSFrom the 10th day of modeling, the volume of both toes started to swell and reached the peak at about 21 days. It was obviously shrunk at about 30 days. Of them, the swelling degree was milder in the MTX group and the FR group than in the model group. Compared with the model group at the same phase, the levels of IL-17 and RANKL decreased in the MTX group after 3 weeks of intervention (P < 0.01, P < 0.05). The IL-17 level decreased in the FR group after three weeks of intervention (P < 0.05). The RANKL level decreased in the MTX group and the FR group after 6 weeks of intervention (P < 0.01, P < 0.05). Compared with the model group and the MTX group, the overall BMD and ankle BMD increased in the FR group after 6 weeks of intervention (P < 0.01, P < 0.05). The ankle ROI/mandible and the toe ROI/mandible were elevated in the FR group after 3 weeks of intervention (P < 0.05). Pathological results suggested that the joint lacunae was significantly widened, the hyperplasia of the synovial tissue was so severe, and the bone tissue was destroyed in the model group. Compared with the model group, the aforesaid conditions were significantly improved in the MTX group and the FR group. The cartilage structure was complete.

CONCLUSIONQR could inhibit decreased BMD, prevent bone destruction, which might be achieved by down-regulating expression levels of IL-17, RANKL, and MIP-1alpha through the osteo immunological Th/RANKL system,inhibiting maturation and differentiation of osteoclasts, thereby, inhibiting bone destruction.