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Dynamics of the inflammatory response after murine spinal cord injury revealed by flow cytometry
Author(s) -
Stirling David P.,
Yong V. Wee
Publication year - 2008
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.21659
Subject(s) - flow cytometry , monocyte , integrin alpha m , spinal cord injury , cd11c , immunology , medicine , spinal cord , inflammation , lymphocyte , pathology , cord blood , biology , phenotype , biochemistry , psychiatry , gene
Spinal cord injury (SCI) triggers a robust inflammatory response that contributes in part to the secondary degeneration of spared tissue. Here, we use flow cytometry to quantify the inflammatory response after SCI. Besides its objective evaluation, flow cytometry allows for levels of particular markers to be documented that further aid in the identification of cellular subsets. Analyses of blood from SCI mice for CD45 (common leukocyte antigen), CD11b (complement receptor‐3), Gr‐1 (neutrophil/monocyte marker), and CD3 (T‐cell marker) revealed a marked increase in circulating neutrophils (CD45 high :Gr‐1 high ) at 12 hr compared with controls. Monocyte density in blood increased at 24 hr, and in contrast, lymphocyte numbers were significantly decreased. Mirroring the early increase in neutrophils within the blood, flow analysis of the spinal cord lesion site revealed a significant ( P < 0.01) and maintained increase in blood‐derived leukocytes (CD45 high :CD11b high ) from 12 to 96 hr compared with sham‐injured and naive controls. Importantly, this technique clearly distinguishes blood‐derived neutrophils (CD45:Gr‐1 high :F4/80 negative) and monocyte/macrophages (CD45 high ) from resident microglia (CD45 low ) and revealed that the majority of the blood‐derived infiltrate were neutrophils. Our results highlight an assumed, but previously uncharacterized, marked and transient increase in leukocyte populations in blood early after SCI followed by the orchestrated invasion of neutrophils and monocytes into the injured cord. In contrast to mobilization of neutrophils, SCI induces lymphopenia that may contribute negatively to the overall outcome after spinal cord trauma. © 2008 Wiley‐Liss, Inc.