Elevated levels of serum hyaluronate and correlation with disease activity in experimental models of arthritis

The serum hyaluronate (HA) concentration was measured in groups of rats immunized for adjuvant or type II collagen arthritis. Serum HA increased as the arthritic lesions developed, correlating with the severity of the disease. This increase in HA was not related to metabolic impairment, because rats with adjuvant arthritis metabolized intravenously administered tritiated HA at a rate similar to that of normal rats. Serum HA levels may be useful as an indicator of synovitis in experimental and possibly in clinical arthritis. Further, this model could serve as an experimental approach for studies of HA metabolism in chronic joint inflammation.