The influence of silicone implantation on murine lupus in MRL lpr/lpr mice

Objective. The use of silicone breast implants has been implicated in the d evelopment of autoimmune connective tissue diseases including systemic lupu s erythematosus (SLE). We examined the influence of implanted silicones in MRL lpr/lpr and MRL +/+ mice. to determine whether silicone increases autoi mmunity and exacerbates experimental lupus. Methods. Mice were implanted with either silicone gel or silicone oil (poly dimethylsiloxane: PDMS), while saline injected mice were used as controls. Proteinuria levels, palpation of lymphadenopathy. serum autoantibodies, cir culating cytokines, and weight change were monitored for 18 weeks, when ter minal glomerulonephritis was evaluated by histopathological techniques. pro teins were extracted from the surface of recovered implants, and the compos ition and immune reactive status of the silicone-binding proteins (SBP) wer e investigated. Results. No adverse influence of silicone gel or silicone oil on the clinic al aspects of lupus was observed. However, anti-DNA antibodies were signifi cantly increased in MRL mice implanted with silicone gel compared to the co ntrol animals, and rheumatoid factor titers were modestly increased in impl anted MRL lpr/lpr mice. Serum cytokine levels were influenced by silicone: implantation in MRL lpr/lpr mice (but not MRL +/+ mice), with interleukin 1 (IL-1) levels increased in gel implanted animals and IL-2 levels elevated in PDMS (silicone oil) implanted mice. Different SEP were detected on impla nts recovered from MRL lpr/lpr mice compared with MRL +/+ mice, and Western blotting revealed the presence of strong autoantibodies to SEP in sera fro m MRL lpr/lpr mice, but not MRL +/+ mice. Conclusion. These findings suggest that silicone implantation may influence immunological responses during murine lupus, including the provocation or exacerbation of autoantibodies However, these immune modifications did not appear to influence the clinical variables of this experimental lupus model .