Biocompatibility of silicone oil and high-density liquids. An immunologic study

Silicone oil and high-density liquids can be useful tools in the treatment of complicated retinal detachments. To test whether these substances induce specific and/or unspecific inflammatory responses, we performed immunoassays on 60 rats of two different inbred strains. After sensitization, each rat was injected in the right foot pad with either silicone oil, fluorosilicone oil, perfluorooctane, or perfluoropolyether. Depending on the inbred strain, the volume of the foot pads increased up to the fifth day, indicating an injection-induced inflammatory reaction. Histopathological examination of rats injected with silicone oil showed infiltration by mononuclear cells and occasional giant cells. In rats receiving fluorosilicone oil, additional eosinophilic reactions were observed. The most pronounced reactions occurred after injection of the two perfluorocarbons, which induced a greater number of giant cells and a slight granulomatous reaction. The degree of tissue response was independent of the type of sensitization; the majority of the draining popliteal lymph nodes showed no enlargement. Our findings demonstrate that all substances tested induced inflammatory though unspecific responses.