The role of macrophages in the absorption process of suture materials: A histological and immunohistochemical study

This study was performed to investigate the cellular interactions between three different suture materials including Poliglecaprone 25 (Monocryl, MN), Polyglycolic acid (Dexon, DX) and Blacksilk (BS), and living tissue regarding the absorption process and biocompatibility of the thread, and to determine the localization of macrophages using ED1 monoclonal antibody. These threads were applied in gluteal muscle closures of thirtysix male Wistar strain rats. Both histological and immunohistochemical observations were performed at the following intervals: 1, 3, 6, 9, 12, and 24 weeks, postoperatively. The absorption of DX occurred in the early experimental phase by the penetration of various amount of ED1-positive macrophages. The absorption of MN was delayed compared with that of the DX, while many ED1-positive macrophages penetrated inside the MN in the mid-experimental phases. Both MN and DX were substantially absorbed at 24 weeks postoperatively with minimal scar tissue. Meanwhile, the BS still remained in the muscular tissue at 24 weeks postoperatively, with a remarkable proliferation of fibrous tissue around the thread. This study suggested that the ED1-positive macrophages played a central role of absorption of MN and DX, and that the MN could possess a superior healing response with a minimum of scar formation.