Local inflammatory response after intramuscularly implantation of anti-adhesive plasma-fluorocarbon-polymer coated Ti6AI4V discs in rats

Abstract

Orthopaedic implants and temporary osteosynthesis devices are commonly based on Titanium (Ti). For short-term devices, cell-material contact should be restricted for easy removal after bone healing. This could be achieved with anti-adhesive plasma-fluorocarbon-polymer (PFP) films created by low-temperature plasma processes. Two different PFP thin film deposition techniques, microwave (MW) and radiofrequency (RF) discharge plasma, were applied to receive smooth, hy-drophobic surfaces with octafluoropropane (C3 F8) or hexafluorohexane (C6 F6) as precursors. This study aimed at examining the immunological local tissue reactions after simultaneous intramus-cular implantation of four different Ti samples, designated as MW-C3 F8, MW-C6 F6, RF-C3 F8 and Ti-controls, in rats. A differentiated morphometric evaluation of the inflammatory reaction was conducted by immunohistochemical staining of CD68+ macrophages, CD163+ macrophages, MHC class II-positive cells, T lymphocytes, CD25+ regulatory T lymphocytes, NK cells and nestin-positive cells in cryosections of surrounding peri-implant tissue. Tissue samples were obtained on days 7, 14 and 56 for investigating the acute and chronical inflammation (n = 8 rats/group). Implants with a radiofrequency discharge plasma (RF-C3 F8) coating exhibited a favorable short-and long-term immune/inflammatory response comparable to Ti-controls. This was also demonstrated by the significant decrease in pro-inflammatory CD68+ macrophages, possibly downregulated by significantly increasing regulatory T lymphocytes.