The previous study of Srnad3 gene knockout mice ( Smad3ex8/ex8 ) shows that the Smad3ex8/ex8 mice develop progressive leukocytosis, periodontitis, gastritis, colitis and chronic infection with abscess formation adjacent to mucosal surfaces . symptomatic mutant mice exhibit thymic involution, enlarged lymph nodes and T cells with activated phenotype.Further study suggests that the thymic cells and peripheral T ceels of Smad3ex8/ex8 mice have lost the response to TGF-β.Furthermore, nwe found that the homologous Smad3ex8/ex mice developed degenerative joint disease resembling human osteoarthritis, osteoporosis and wound healing up quicker. So the mice can serve as an ideal animal model for immune dysregulation, osteoarthritis and so on.