Increased serum immunoreactive prolyl hydroxylase in rats with carrageenan-induced granuloma and adjuvant arthritis

The authors developed a competitive enzyme immunoassay for serum immunoreactive prolyl hydroxylase (SIRPH) as a marker of fibrogenesis, and examined the changes in SIRPH concentrations in rats with carrageenan-induced granuloma and adjuvant arthritis. The effects of such anti-inflammatory agents as prednisolone, pranoprofen, indomethacin, and hydrocortisone were also investigated. Prolyl hydroxylase activity in rats with carrageenan-induced granuloma and adjuvant arthritis increased inflammatory granulation tissue, and the concentrations of SIRPH also increased time dependently. The nontreated controls showed a constant low level of SIRPH. After treatment with anti-inflammatory agents or removal of the granuloma, SIRPH levels decreased coincident with the improvement of clinical symptoms. It was assumed that immunoreactive prolyl hydroxylase was released into the blood stream as a result of increased turnover of the enzyme protein owing to fibrotic disorders. SIRPH could be a useful biochemical marker for assessing therapeutic effects through the actual activity of fibrogenesis.