Spontaneous degenerative polyarthritis in male New Zealand black/KN mice.

Histopathologic studies and radiographic analysis revealed that male New Zealand black/KN (NZB/KN) mice develop degenerative polyarthritis in the joints of the forepaw and hindpaw beginning at age 2 months. Deposits of autoantibodies were observed on proliferating collagen fibers, nuclei of chondrocytes, and epidermal cells. Increases in the frequency of positivity for rheumatoid factor and anti-type II collagen antibodies and in the level of serum oxidation activity were noted in these mice. The joint disease in male NZB/KN mice was transferable to female NZB/KN mice and male BALB/c mice by intraperitoneal injection of spleen cells from the male NZB/KN mice. This animal model of arthritis will be extremely useful for analyzing not only the pathogenesis of rheumatoid arthritis, but also new strategies for its treatment, since NZB/KN mice, unlike MRL/lpr mice, do not develop severe lupus nephritis or lymph-adenopathy, and therefore have a longer survival period.