Department of Surgery, Nordland Hospital, Bodø, Norway.
Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway.
Front Immunol. 2024 Jul 19;15:1396800. doi: 10.3389/fimmu.2024.1396800. eCollection 2024.
Bone marrow embolization may complicate orthopedic surgery, potentially causing fat embolism syndrome. The inflammatory potential of bone marrow emboli is unclear. We aimed to investigate the inflammatory response to femoral intramedullary nailing, specifically the systemic inflammatory effects in plasma, and local tissue responses. Additionally, the plasma response was compared to that following intravenous injection of autologous bone marrow.
Twelve pigs underwent femoral nailing (previously shown to have fat emboli in lung and heart), four received intravenous bone marrow, and four served as sham controls. Blood samples were collected hourly and tissue samples postmortem. Additionally, we incubated bone marrow and blood, separately and in combination, from six pigs . Complement activation was detected by C3a and the terminal C5b-9 complement complex (TCC), and the cytokines TNF, IL-1β, IL-6 and IL-10 as well as the thrombin-antithrombin complexes (TAT) were all measured using enzyme-immunoassays.
After nailing, plasma IL-6 rose 21-fold, compared to a 4-fold rise in sham (p=0.0004). No plasma differences in the rest of the inflammatory markers were noted across groups. However, nailing yielded 2-3-times higher C3a, TCC, TNF, IL-1β and IL-10 in lung tissue compared to sham (p<0.0001-0.03). Similarly, heart tissue exhibited 2-times higher TCC and IL-1β compared to sham (p<0.0001-0.03). Intravenous bone marrow yielded 8-times higher TAT than sham at 30 minutes (p<0.0001). , incubation of bone marrow for four hours resulted in 95-times higher IL-6 compared to whole blood (p=0.03).
A selective increase in plasma IL-6 was observed following femoral nailing, whereas lung and heart tissues revealed a broad local inflammatory response not reflected systemically. experiments may imply bone marrow to be the primary IL-6 source.
骨髓栓塞可能使矫形外科手术复杂化，并可能导致脂肪栓塞综合征。骨髓栓塞的炎症潜能尚不清楚。我们旨在研究股骨髓内钉固定术引起的炎症反应，特别是血浆中的全身炎症反应，以及局部组织反应。此外，将血浆反应与静脉内注射自体骨髓进行了比较。
12 头猪接受了股骨髓内钉固定术（先前在肺和心脏中发现有脂肪栓塞），4 头接受了静脉内注射骨髓，4 头作为假手术对照。每小时采集血样，死后采集组织样本。此外，我们还分别和组合培养了来自 6 头猪的骨髓和血液。通过 C3a 和末端 C5b-9 补体复合物（TCC）检测补体激活，使用酶免疫测定法检测 TNF、IL-1β、IL-6 和 IL-10 以及凝血酶-抗凝血酶复合物（TAT）。
与假手术组（p=0.0004）相比，骨髓内钉固定术后血浆中 IL-6 增加了 21 倍，而其余炎症标志物在各组之间无差异。然而，与假手术组相比，骨髓内钉固定术导致肺组织中 C3a、TCC、TNF、IL-1β 和 IL-10 增加了 2-3 倍（p<0.0001-0.03）。同样，心脏组织中的 TCC 和 IL-1β 也比假手术组增加了 2 倍（p<0.0001-0.03）。静脉内注射骨髓后 30 分钟，TAT 比假手术组高 8 倍（p<0.0001）。4 小时孵育骨髓后，IL-6 比全血高 95 倍（p=0.03）。
股骨髓内钉固定术后观察到血浆中 IL-6 选择性增加，而肺和心脏组织则表现出广泛的局部炎症反应，而没有全身反应。这些实验可能暗示骨髓是 IL-6 的主要来源。
