Stability analysis of a model for foreign body fibrotic reactions

Influence of chlorhexidine digluconate on biocompatibility of cements: Morphological and immunohistochemistry analysis

In this study, the in vivo biocompatibility was evaluated by using conventional ionomer cements modified with Chlorhexidine (CHX) in different time intervals. In total, 105 male Wistar rats were randomized into seven groups: control, groups M, M10, M18 and groups RL, RL10, RL18 (M-Meron and RL-RivaLuting, and added CHX-10% and CHX-18%, respectively). Histological analyses of inflammatory infiltrate and collagen fibers, and immunohistochemistry of CD68+ for macrophages (MOs) and multinucleated giant cells (MGCs) were performed. Data were analyzed using the Kruskal-Wallis and Dunn (p < .05) tests. Intense inflammatory infiltrate was demonstrated in Group Riva CHX-18% within 7 and 15 days (p < .05), without differences after 30 days. For collagenization, healing of the groups was compatible with that of control in 15 and 30 days (p > .05). Immunomarking of CD68+ was more significant in the groups with higher concentration of CHX. There was significant difference in quantity of MGCs in groups with 18% CHX, Meron (p = .001) in 7 days, and in Riva at 30 days (p = .001). Significant difference was also found in quantities of MOs in Groups Meron and Riva in 7 days (p = .001), and only in Riva at 15 and 30 days (p = .001). The cements with addition of CHX demonstrated biocompatibility with tissues. Riva CHX-18% had the most effect on cells of the inflammatory process but showed satisfactory tissue repair.

Effect of Yellow Propolis on Biocompatibility of Cements: Morphological and Immunohistochemistry Analysis

Objective  The focus of this study was to evaluate the biocompatibility of ionomer cements modified with ethanolic extracts of propolis (EEP) in different concentrations and time intervals.

Materials and Methods  In total, one hundred and thirty-five male Wistar rats were randomized into nine groups: Control, Groups Meron, and Groups Ketac (conventional, and added with 10, 25, 50% EEP, respectively). Histological analyses of inflammatory infiltrate and collagen fibers, and immunohistochemistry of CD68+ for macrophages (MOs) and multinucleated giant cells (MGCs) were performed.

Statistical Analysis  Data were analyzed using the Kruskal—Wallis and Dunn ( p < 0.05) tests.

Results  Intense inflammatory infiltrate was demonstrated in the cements with 10% EEP at 7 days and 15 days ( p < 0.05), only Group Ketac 10% EEP ( p = 0.01) at 30 days. A smaller quantity of collagen fibers was observed in the cements with 10% EEP ( p = 0.01) at 7 days, and Group Meron 10% EEP ( p = 0.04) at 15 days. MOs and MGCs showed significant difference for the cements with 10% EEP ( p = 0.01) at 7 and 15 days. At 30 days, MOs persisted in the Groups with 10% EEP.

Conclusions  The concentration of 10% EEP had the greatest influence on the inflammatory and tissue repair processes. The concentrations of 25 and 50% EEP demonstrated biocompatibility similar to that of cements that did not receive EEP.

A computational model of fibroblast and macrophage spatial/temporal dynamics in foreign body reactions

The implantation of medical devices often triggers several immune responses, one kind of which is categorized as foreign body reactions. It is well established that macrophages and many other cells participate in the complex processes of foreign body reactions, and cause severe inflammations and fibrotic capsule formation in surrounding tissues. However, the detailed mechanisms of macrophage responses, recruitment and activation, in foreign body reactions are not totally understood. In the meantime, mathematical models have been proposed to systematically decipher the behavior of this complex system of multiple cells, proteins and biochemical processes in wound healing responses. Based on these early works, this study introduces a mathematical model in two spatial dimensions to investigate the transient behavior of macrophages, fibroblasts and their interactions during the formation of fibrotic tissue. We find that the simulation results are consistent with the experimental observations. These findings support that the model can reveal quantitative insights for studying foreign body reaction processes.