Objectives: Both collagen-induced arthritis (CIA) and pristane-induced arthritis (PIA) are commonly used rat models of rheumatoid arthritis (RA). The aim of this study was systematically to compare the differences between CIA and PIA in Dark Agouti (DA) rats.
Methods: The CIA was induced by immunising DA rats intradermally with collagen type (C) and PIA was induced by injecting subcutaneously with pristane. The arthritis was evaluated macroscopically and microscopically. Nitric oxide (NO) level of plasma was determined by Griess reaction method. Plasma autoimmune antibodies, including C specific IgG antibody (anti-C IgG), cyclic citrullinated peptide specific IgG antibody (anti-CCP IgG), IgM and IgG rheumatoid factors (IgM RF and IgG RF), were detected by the enzyme-linked immunosorbent assay.
Results: The onset of PIA rats was earlier than that of CIA rats. The involved sites of PIA rats were mostly wrist/ankle and metacarpophalangeal/metatarsophalangeal (MCP/MTP) joints while those of CIA rats were primarily distal interphalangeal (DIP) joints. NO level of plasma was increased in PIA rats, as anti-C IgG, anti-CCP IgG, IgM RF and IgG RF levels of plasma were increased in CIA rats. The kidney hyaline casts were more frequent in CIA rats than in control rats, with 9/12 in PIA group, 8/8 in CIA, and 4/8 in control, respectively.
Conclusions: PIA mainly affected wrist/ankle joints and MCP/MTP joints, had more severe inflammation and hardly involved other organs; while CIA mostly influenced DIP joints, had more autoimmune antibodies in plasma, and always showed hyaline casts in kidney. These findings will be useful to select the animal model of RA.