[Effect of moxibustion on the expressions of hypoxia inducible factor-1α and vascular endothelial growth factor in ankle synovial tissue of rats with adjuvant arthritis].

Objective: To observe the effect of moxibustion on the expressions of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in ankle synovial tissue of rats with adjuvant arthritis(AA), so as to explore the mechanism of moxibustion in inhibiting synovial angiogenesis and improving joint symptoms of rheumatoid arthritis.

Methods: Sixty healthy male SD rats were randomly divided into normal group, model group, moxibustion group and medication group, with 15 rats in each group. AA rat model was established by subcutaneous injection of Freund's complete adjuvant into the right hind paw. Rats in the moxibustion group were treated with "Zusanli" (ST36), "Guanyuan" (CV4) and "Ashi" point moxibustion, 20 min each time, once a day, for consecutive 3 weeks. Rats in the medication group were given methotrexate (0.35 mg/kg) intragastric administration, twice a week, for consecutive 3 weeks. Foot plantar volume of rats was measured by toe volume mea-suring instrument. HE staining was used to observe the histopathology of ankle synovium. The protein expressions of HIF-1α and VEGF in ankle synovial tissue were detected by immunohistochemistry and Western blot.

Results: Compared with the normal group, the foot plantar volume and the protein expressions of HIF-1α and VEGF in synovial tissue of ankle joint were significantly increased (P<0.01) in the model group, the synovial tissue showed obvious hyperplasia and a large number of neovasculogenesis. Following the interventions, the foot plantar volume and the protein expressions of HIF-1α and VEGF in synovial tissue of ankle joint were significantly decreased (P<0.05, P<0.01) in both moxibustion and medication groups in contrast to the model group, and there was no obvious proliferation of synovial tissue, and only a few neovascularization was observed. Compared with the medication group, the foot plantar volume was decreased (P<0.05) in the moxibustion group.

Conclusion: Moxibustion can improve joint swelling and inhibit synovial angiogenesis in AA rats, and its mechanism may be related to down-regulating of HIF-1α and VEGF protein expressions.