Abstract
Development of experimental animal models for human diseases has strongly accelerated the advance of basic and clinical studies. MRL/l mice develop lupus erythematosus lesion, vasculitis, arthritis, and lymphoma spontaneously. MRL/l mice possess serological and immunological abnormalities such as antinuclear antibodies, anti-DNA, anti-Sm, rheumatoid factor, cryoglobulins, immune complex, hypergammaglobulinemia, per se.
As for inflammatory lesions, MRL/l mice had subacute glomerulonephritis in which the mesangial cell proliferation was conspicuous. Electron microscopic study revealed the deposition of electron-dense material on the subendothelial side of the glomerular basement membrane and in the mesangial cells. In the fluorescein study, granular deposition of IgG, IgM, and C 3 was noticed along the basement membrane and in the mesangial cells. Vasculitis was seen in entire body. Histopathologically, it was vasculitis characterized by granulation and round cell infiltration. Panarteritis and fibrinoid necrosis were also identified in some sections, indicating that the vasculitis resembled human periarteritis nodosa. The peripheral joints were principal sites of the arthritis seen in MRL/l mice. The histopathological changes of the affected joints resembled one of the histopathological types of human rheumatoid arthritis, i.e. “lympho-plasmocytes reaction accompanied with connective tissue proliferation”. It was presumed the this arthritis might be located between human rheumatoid arthritis and rat adjuaant arthritis.
MRL/l mice will serve as useful and important experimantal animal model to elucidate pathogenesis and establish treatments for inflammation and immunological disorders.
