Lipopolysaccharide impairs fracture healing: An experimental study in rats

Abstract

Background: It has been shown that trauma causes translocation of lipopolysaccharide (LPS) endotoxins from the gut. LPS has been identified as a major bacterial bone resorbing factor. The effects of LPS on bone healing are therefore of clinical interest, as trauma involving fractures followed by sepsis is a clinical scenario. We investigated the effects of systemic and local administration of LPS on the healing of femoral fractures in rats. Animals and methods: In 3 groups, each consisting of 9 rats, a mid-diaphyseal osteotomy/fracture of the femoral bone was performed and then nailed. In one group of animals, LPS was applied intraperitoneally (systemically), and in another group, LPS was applied locally at the fracture site. The third group served as a control. The animals were killed after 6 weeks, and the mechanical characteristics of the healing osteotomies were evaluated. Results: We found that LPS induced a hypertrophic and immature callus, as evaluated by bone mineral content and density. In the rats given LPS intraperitoneally, the mechanical strength characteristics were reduced, as evaluated by bending moment, rigidity, and energy absorption. Interpretation: The rats given LPS intraperitoneally reflect a clinical situation with fracture trauma and endotoxinemia. Our findings indicate that endotoxinemia may impair the fracture healing processes. Copyright© Taylor & Francis 2005.