A new model of AA-amyloidosis induced by oral pristane in BALB/c mice.

Fifteen male BALB/c mice were given six intermittent oral doses of O.I. ml pristane (2, 6, 10, 14 tetramethylpentadecane) within a period of 9 weeks. Fifteen mice receiving tap water using the same schedule formed the control group. Amyloidosis was first detected in the spleen of a mouse which had died 33 weeks after the first dose and 24 weeks after the last. All six mice which were subsequently autopsied 34-51 weeks after the first dose also showed amyloidosis involving liver and spleen. The most extensive tissue deposits were seen at 37-38 weeks whereas the older mice showed predominantly chronic renal lesions with papillary necrosis, scars and cystic change. Electron microscopy confirmed the identity of the amyloid fibrils and the presence of globular stellate amyloid 'bodies' in liver and spleen. The amyloid deposits were shown to be made up of AA (amyloid associated) protein using an indirect immunoperoxidase method and a monoclonal rat anti-murine AA protein antibody. We did not find any plasmacytomas or increased numbers of plasma cells in the bone marrow. None of the control mice developed amyloidosis. This new experimental model promises to provide a means of studying several aspects of secondary amyloidosis which may be relevant to the clinical situation.