Splenic response to silicon drain material following intraperitoneal implantation

To study the splenic response to intraperitoneal biomaterials, 100% silicon rubber drain fragments were intraperitoneally implanted in the rat. Four days after implantation, specimens of the spleen and implanted rubber fragment were retrieved and subjected to scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis (EDX). In SEM, macrophages with membrane fusion and cytoplasmic spreading were noted on the surfaces of implanted rubber fragments. Specimens of the spleen from animals with implants showed light 3-10-microns structures that were not observed in those without implants. EDX revealed the presence of silicon both in the rubber fragment and in the spleen of the implanted animals. Both light microscopy and transmission electron microscopy showed a large number of particles inside giant cells of the spleen. The present study demonstrated an active transport of rubber fragments containing silicon from the peritoneal cavity to the spleen by adherent macrophages, reflecting a splenic response to intraperitoneal implantation of biomaterials. The modes of silicon rubber degradation and transportation remain to be elucidated.