Tissue response to a novel bone adhesive implanted subcutaneously in rats: A histological and gene expression analysis

Abstract

AbstractMedian sternotomy provides access to the heart and surrounding valves for cardiothoracic surgery. However, complications arise such as micro‐motion and separation between the two sternal halves. To prevent these complications, the use of a bone adhesive has been proposed to augment the mechanical union of the two sternal halves when combined with wire cerclage. Our group has developed a bone adhesive for sternal fixation, utilizing a glass polyalkenoate cement (GPC) based on a zinc silicate ionomeric glass (mole fraction: SiO2:0.48, ZnO:0.36, CaO:0.12, SrO:0.04). Here we present the first soft‐tissue biological safety assessment of this novel Sr/Zn‐GPC, where we implanted the material subcutaneously in rats for 6 and 12 weeks. Polymethyl‐methacrylate (PMMA) bone cement was used as a baseline control with respect to inflammation and biocompatibility. Histological assessment revealed no adverse tissue reaction nor ectopic bone formation in response to the novel material. Additionally, relative expression of pro‐inflammatory and osteogenic genes (Col1a1, SOX9, Runx2, IL‐1, IL‐6, and TNF‐α) was assessed in the tissue surrounding implants and revealed no significant differences in expression between the Sr/Zn‐GPC and PMMA implants.