Background: Abdominal injuries combined with bone fractures are increasing. Splenectomies are often required, but have prolonged healing time for bone fracture.
Objectives: The aim of the study was to explore the molecular mechanism for splenectomy delaying fracture healing.
Material and methods: Eighty-four patients (42 received splenectomy) who received hip fractures operations were recruited in our hospital. One-year follow-up analysis was performed. To ensure the results, an animal model was established. Sprague-Dawley (SD) rats were randomly divided into 5 groups: group A: experimental group, femoral fractures + splenectomy; group B: femoral fractures; group C: splenectomy; group D: femoral fracture + sham splenectomy; group E: sham fracture. After the femoral fracture surgery, the callus status was evaluated by X-ray.
Results: After 1-year follow-up, the healing index and bone quality was higher in the fracture-operatedonly group than in the splenectomy group. In contrast, the rate of healing complications was lower in the fracture-operated-only group than in the splenectomy group. Biomarker analysis showed that the serum levels of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and bone morphogenetic protein (BMP) were higher in the fracture-operated-only group than in the splenectomy group. No difference of the callus status was found among the rats in groups B, D and E (p > 0.05), while there were significant differences of the callus status of the rats in groups A and C at different stages (p < 0.05). On the other hand, the levels of TNF-α, IL-6 and BMP increased, reached peak after 7-day splenectomy surgery, and then decreased significantly in groups A and C (p > 0.05).
Conclusions: Splenectomy delays fracture healing by affecting the levels of TNF-α, IL-6 and BMP.
Keywords: bone morphogenetic protein; fracture; immune function; splenectomy; tumor necrosis factor-alpha.