Abstract
Osteolysis, that is, progressive periprosthetic bone loss, is responsible for approximately 70% of aseptic loosening and implant failure. Usually, it is due to a granulomatous reaction wear‐induced, leading to macrophage and osteoclast‐mediated bone resorption. At present, there is no established prophylaxis or treatment for this process. For this purpose, as a preliminary investigation, we aimed to study the effects in two directions, inhibition of proinflammatory signals, and bone remodeling activity, of two newly synthesized anthraquinone molecules [N,N′‐Diethylamino‐2,6‐anthraquinone‐disulfonamide (GR375) and N,N′‐(p‐ethoxyphenyl)‐2,6‐anthraquinone‐disulfon amide (GR377)]. Among the pro‐inflammatory signals, the ability of the two anthraquinones to interfere with the production of superoxide anion (O~2~^−^), which was assumed as a marker of reactive oxygen species (ROS), was evaluated in an in vitro cell model by testing phagocytes, such as human neutrophils, challenged by the chemotactic agent N‐formylmethionyl‐leucyl‐phenylalanine (FMLP). Both compounds inhibited O~2~^−^ production, in a dose‐dependent way, without exerting scavenger effects. An in vivo model was applied to investigate their effect on bone remodeling. Fifty‐four female Wistar rats were divided into eight groups of six animals each, and a 4‐week treatment was applied in two phases. A 25 mg/kg/os dose in the first phase and 12.5–6.25mg/kg/os doses in the second one were employed. The tibia trabecular bone at the secondary spongiosa level was analyzed, and trabecular bone volume (%TBV), trabecular thickness (TbTh), and apatite lattice parameters were measured. At the highest doses of GR375 and GR377 the %TBV and the TbTh increased by 33.2, 34.6%, and 3.6 and 9.1%, respectively, whereas crystallographic parameters were not significantly different from the untreated group. Our results suggest a simultaneous antiinflammatory and antiosteoclastic activity of both drugs that encourages to perform further research. If it will be confirmed, they could be proposed in a variety of bone diseases, in particular, when acute inflammation is associated to osteolytic processes and, eventually, in the prevention and treatment of periprosthetic osteolysis. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005