These mice were chosen as a rheumatoid arthritis animal model because this transgenic (Tg) mouse overexpresses human TNF-alpha and develops erosive polyarthritis with many characteristics observed in rheumatoid arthritis patients, which has already been widely used for dissecting the molecular mechanisms of the pathogenic process and evaluating the efficacy of novel therapeutic strategies for rheumatoid arthritis [31]. This evidence concerns the gene TNF and polyarticular arthritis.