OBJECTIVETo investigate the effects of oral administration of type II collagen (CII) on adjuvant arthritis (AA) in rats and its mechanisms, and to compare the effects of CII with those of the Chinese traditional medicine Tripterygium Polyglycoside administered similarly.

METHODSArthritis was induced in rats by immunization using Freund's complete adjuvant (FCA). After feeding rats either soluble CII or Tripterygium Polyglycoside, changes in degree of articular swelling and articular histological findings were observed in AA rats. Some correlative immunological indexes were measured, including delayed type hypersensitivity (DTH) reaction, anti-collagen and anti-Mycobacterium tuberculosis (MT) antibody in serum, and levels of IFN-gamma and TNF-alpha in articular steep in rats.

RESULTSOral administration of CII was able to alleviate both distinctly articular and general symptoms in AA rats, suppress synovium hyperplasia and inflammatory cells infiltration in arthrosis capsule. The effects brought about by CII were stronger than those by Tripterygium Polyglycoside. Oral administration of CII inhibited antigen-specific immune response, such as DTH and antibody reaction to CII. In addition, the expression of IFN-gamma and TNF-alpha in joints were locally downregulated.

CONCLUSIONSThe therapeutic effect of oral administration of CII is obvious on adjuvant arthritis in rats. Its remedial mechanisms are likely related to the downregulation of both IFN-gamma and TNF-alpha, and the suppression of cell immunity.