Kern P M, Keilholz L, Forster C, Hallmann R, Herrmann M, Seegenschmiedt M H
Institute for Clinical Immunology and Rheumatology, University of Erlangen-Nürnberg, Universitätsstrasse 27, 91054, Erlangen, Germany.
Radiother Oncol. 2000 Mar;54(3):273-82. doi: 10.1016/s0167-8140(00)00141-9.
The anti-inflammatory effect of low-dose radiotherapy (LD-RT) still is not understood. The adhesion of leukocytes to endothelial cells (EC) of the vessel wall is the initial event of tissue invasion, and thus, crucially contributes to the regulation of inflammation. We investigated the influence of LD-RT on the adhesion process in vitro.
Isolated peripheral-blood-mononuclear-cells (PBMC) were incubated with an activated murine endothelioma cell-line under shear conditions at 4 degrees C after irradiation with single doses between 0.1 and 10.0 Gy. Adherent cells were counted microscopically and compared to a non-irradiated control. In parallel, viability and expression of adhesion molecules, especially of L-selectin, and lineage-specific markers on the cell surface were determined by dye exclusion and cytofluorometry, respectively. Modulation of adhesion by soluble L-selectin was tested in the adhesion assay.
Radiation doses of 0.1-0.5 Gy reduced the adhesion of viable PBMC to EC in vitro by 70% of the control level 4 h after irradiation. Leukocytes showed a marked reduction of L-selectin expression after LD-RT. Soluble L-selectin can inhibit the adhesion of PBMC to EC.
The anti-inflammatory effect of LD-RT might, in part, be due to the reduction in the adhesion of PBMC to EC. This reduction in adhesion might be a consequence of the reduced expression of L-selectin on the surface of PBMC, and the inhibition of adherence by soluble L-selectin shed by PBMC in vitro.
低剂量放疗（LD-RT）的抗炎作用仍未明确。白细胞与血管壁内皮细胞（EC）的黏附是组织侵袭的起始事件，因此对炎症调节起着关键作用。我们在体外研究了低剂量放疗对黏附过程的影响。
将分离的外周血单核细胞（PBMC）在4℃的剪切条件下，与活化的小鼠内皮瘤细胞系一起孵育，照射剂量为0.1至10.0 Gy的单剂量。通过显微镜计数黏附细胞，并与未照射的对照组进行比较。同时，分别通过染料排除法和细胞荧光测定法测定细胞活力以及黏附分子尤其是L-选择素的表达，还有细胞表面的谱系特异性标志物。在黏附试验中测试可溶性L-选择素对黏附的调节作用。
0.1 - 0.5 Gy的辐射剂量在照射后4小时使体外存活的PBMC与EC的黏附减少至对照水平的70%。低剂量放疗后白细胞的L-选择素表达明显降低。可溶性L-选择素可抑制PBMC与EC的黏附。
低剂量放疗的抗炎作用可能部分归因于PBMC与EC黏附的减少。这种黏附减少可能是PBMC表面L-选择素表达降低以及体外PBMC释放的可溶性L-选择素对黏附的抑制作用的结果。
