Therapeutic effects of Hominis placenta injection into an acupuncture point on the inflammatory responses in subchondral bone region of adjuvant-induced polyarthritic rat

Abstract

Rheumatoid arthritis (RA) is characterized by chronic inflammation of the synovial membrane in the joint, which leads to the progressive destruction of articular cartilage, ligament and bone. Several cytokines such as tumor necrosis factor alpha (TNF-alpha), interleukin 1beta (IL-1beta), and interleukin 6 (IL-6) have been implicated in the pathological mechanisms of synovial tissue proliferation, joint destruction and programmed cell death in rheumatoid joint. In the Korean traditional medicine, Hominis placenta (HP) as an herbal component of herb-acupuncture has been widely used to treat chronic inflammatory diseases such as RA. To study the therapeutic effects of HP injection into the ST36 acupoint (HP herb-acupuncture) on the inflammatory responses of a subchondral region of rheumatoid joint, the polyarthritis-induced Sprague-Dawley (SD) rat was developed as a rheumatoid arthritis model by the intradermal injection of dried cells of Mycobacterium tuberculosis emulsified in squalene to the base of tail. After the onset stage (11 d after adjuvant injection) of polyarthritis, a fixed volume of HP extract was daily injected to Zusanli (ST36) acupoint on the rat's leg for 2 weeks. The body weight, paw volume of the knee joint and articular index were exploited as an assessment method addressing arthritic symptoms, and the expression profiles of TNF-alpha, IL-1beta and IL-6 at the subchondral bone of the joint were analyzed using an immunohistochemistry. After the treatment of arthritic rats with HP, the body weights and paw volumes of arthritic rats were almost restored to the levels of normal rats whereas the evaluation by the articular index was not remarkable. The TNF-alpha, IL-1beta and IL-6 positive cells in the immunohistological sections of subchondral bone region of the joint significantly decreased in HP-treated (ST36 acupoint) arthritic group as compared with those in non-treated or HP-treated (non-acupoint) ones, which was coincident with the behavioral studies. In conclusion, the HP herb-acupuncture was found to be effective to alleviate the arthritic symptoms in adjuvant-induced arthritis rats as regards the body weight, joint appearance and the expression profiles of inflammatory cytokines.