Background: Capsule formation around breast implants, development of tendon adhesions after tendon repair, intestinal brits after laparatomies, hypertrophic scars in skin incisions all are the results of excessive collagen synthesis to the extracellular matrix by fibroblasts. Any intervention that leads to cessation of collagen synthesis in these clinical situations may help to prevent these untoward results of wound healing. Although 5-fluorouracil (5-FU) is used mainly as a cytotoxic drug in chemotherapy protocols, it decreases cellular metabolism and blocks protein synthesis only at lower concentrations. Findings have shown that 5-FU downregulates fibroblast proliferation and differentiation in vitro. It has been used to treat fibroproliferative disorders of the eye and skin and is thought to inhibit thymidylate synthetase, blocking DNA replication.
Methods: This study used five treatment groups: (1) gelatin only, (2) silicone only, (3) silicone + gelatin, (4) silicone + gelatin containing 1 mg of 5-FU, and (5) silicone + gelatin containing 5 mg of 5-FU. The release kinetics of 5-FU from gelatin have been investigated by means of ultraviolet spectrophotometric analysis. Specimens were obtained on postoperative day 30. Gross evaluation and histopathologic examination were conducted for capsule formation and the development of inflammation.
Results: The silicone group had the most prominent capsule formation among all the groups. The gelatin group was second, and the silicone + gelatin group was third. As compared with the other groups, the 5-FU-containing groups had the least capsule formation. The 5-mg 5-FU-containing group had the most inflammation. The silicone + gelatin group was second in inflammation. Although the silicone, gelatin, and 1-mg 5-FU-containing groups had the same means, the results of the silicone group showed the most divergent data within the group.
Conclusions: Because 5-FU loaded to a gelatin carrier for its slow release seems to prevent capsule formation around silicone blocks, it may be used to prevent capsule formation around silicone breast implants.