The effect of a subcutaneous silicone rubber implant with shallow surface microgrooves on the surrounding tissues in rabbits

Abstract

It has been suggested that during wound healing microtextured surfaces can alter events at the interface be­ tween implant surface surface and surrounding tissues. To investigate this phenomenon, smooth and microtextured silicone rubber implants were implanted subcutaneously in rabbits for 3, 7, 42, and 84 days. The textured implants pos­ sessed parallel surface microgrooves and ridges with a width of 2.0, 5.0, and 10.0 \x.m. All gi'ooves had a depth of approximately 0.5 jxm. SEM observation showed fibroblasts, erythrocytes, lymphocytes, macrophages, fibrin, and colla­ gen on all implant surfaces after 3 and 7 days. After 42 and 84 days only little collagen, a small number of fibroblasts, but no inflammatory cells were seen on the implant surfaces. The fibroblasts were not oriented along the surface grooves on all textured surfaces. Three-dimensional reconstruction of CLSM images and LM images showed no significant dif­ ferences between the thickness of the capsules surrounding the smooth and those surrounding the microgrooved im­ plants. In contrast, LM did show a significantly lower num­ ber of inflammatory cells and a significantly higher number of blood vessels in the capsules surrounding the micro­ grooved implants. Differences between the 2,0, 5,0, and 10.0 jxm grooved implants were not detected. Our results con­ cerning the capsule thickness suggest that the depth of our grooves was not sufficient to facilitate mechanical interlock­ ing, but the cause for the observed differences in inflamma­ tory response and number of blood vessels remains unclear. IN T R O D U C T IO N The interaction between an implant material and the surrounding tissues can be considered vital for the final clinical performance of implanted artificial medi­ cal devices. For example, the promotion of tissue at­ tachment and the concomitant reduction of the highly undesirable chronic inflammatory response and fibro­ sis around implant materials are of central importance for the biocompatibility of biomaterials.1 Since various surface properties2 of an implant material determine the biocompatibility of these materials, surface modi­ fications based on the most recent technologies are being explored in search of the ideal implant surface.3 This study will focus on one of these modifications, i.e. implant surface texturing on a micrometer scale. Earlier studies have shown that microgeometrical

Mice that lack the angiogenesis inhibitor, thrombospondin 2, mount an altered foreign body reaction characterized by increased vascularity

“…Picha et al (34) have shown that pillared surface texturing of silicone results in reduced fibrosis and increased vascularization in close proximity to the implant. den Braber et al (35) created microgrooves on silicone rubber implants, thereby increasing the vascularity of the resulting capsules. Karp et al (36) observed the presence of capillaries in capsules that formed around implanted Millipore filters.…”

Surface Engineering and Modification for Biomedical Applications

“…Various studies have demonstrated that although different cell types behave differently, texturing has strong orientation effects on the cell functions such as migration, proliferation, differentiation and apoptosis and cytoskeleton elements [61][62][63][64][65][66][67][68][69][70][71][72]. Transmission electron microscopy (TEM) studies have demonstrated that cells penetrate into very shallow (≤1 μm) or wide (≥5 μm) microgrooves, wrapping around flat walls or edges.…”

Cell and tissue behavior on micro-grooved surfaces

“…Den Braber et al, 82 Walboomers et al, 83 and Walboomers and Jansen 84 evaluated the influence of microgrooves on the formation of fibrous capsules around subcutaneous implants inserted in rabbits, guinea pigs, and goats. The results of these studies suggested that microgrooves were unable to influence the wound healing process.…”