Characterization of two experimental rodent models for evaluating novel drugs for rheumatoid arthritis

Rodent models are widely used to evaluate molecular mechanisms of rheumatoid arthritis (RA) and potential new therapeutic drugs. In our context, we developed and characterized two experimental models in Lewis rats, adjuvant arthritis (AA) and collagen-induced arthritis (CIA), to assess novel biotechnology drugs for RA treatment. We evaluated clinical signs and histological damage in animals. Specific antibody production and cytokine profile of T cells were also determined. All the Lewis rats developed arthritis following a subcutaneous injection of type II collagen (CII) or Mycobacterium tuberculosis and showed a swelling rate of more than 100% at the hind paws. Data showed a faster course of arthritis and a more severe inflammatory response in the AA model compared to the CIA model. In both models, the formation of the pannus and osteoclast hyperplasia was observed. A strong antibody response to CII was detected in the CIA model. We also observed a pronounced skewing of the cytokine balance towards Th1 in both experimental models. These findings suggest that inflammatory response in the AA model is more severe than in the CIA model but both are useful in assessing new biotechnology drugs for RA treatment.