Imaging changes in lymphoid organs in vivo after brain ischemia with three-dimensional fluorescence molecular tomography in transgenic mice expressing green fluorescent protein in T lymphocytes.
Stroke induces a strong inflammatory reaction in the brain and depresses the immune system. We sought to assess longitudinal changes in T-cell numbers in the lymphoid organs of living mice after brain ischemia. Middle cerebral artery occlusion was carried out in transgenic mice expressing green fluorescent protein (GFP+) in the T-cell population under the control of the hCD2 locus control region. Imaging was performed by three-dimensional fluorescence molecular tomography (FMT) before and at several time points after ischemia or sham operation and in controls. At day 7, GFP+ cell content in lymphoid organs was measured postmortem by flow cytometry. GFP+ cell numbers and in vivo FMT signal intensity were reduced at day 7 after ischemia and, to a lesser extent, after sham operation. Linear regression analysis demonstrated that postmortem GFP+ cell numbers and corresponding in vivo FMT data were significantly correlated in the thymus (r2 = .65, p < .0001) and lymph nodes (r2 = .67, p < .0001). These relationships allowed inferring the number of GFP+ T cells from in vivo FMT data. The results show the time course reduction of T-cell content in the lymphoid organs of living mice, providing in vivo evidence of lymphoid organ atrophy after stroke and, to a lesser extent, after head surgery with craniectomy and dura mater opening in sham-operated mice.
Martin
Abraham
A
Institut d'Investigacions Biomèdiques de Barcelona, Barcelona, Spain.
Aguirre
Juan
J
Sarasa-Renedo
Ana
A
Tsoukatou
Debbie
D
Garofalakis
Anikitos
A
Meyer
Heiko
H
Mamalaki
Clio
C
Ripoll
Jorge
J
Planas
Anna M
AM
D000704:Analysis of Variance; D000818:Animals; D002545:Brain Ischemia / Q000276:immunology / Q000473:pathology*; D004195:Disease Models, Animal; D005260:Female; D005453:Fluorescence; D049452:Green Fluorescent Proteins / Q000378:metabolism; D021621:Imaging, Three-Dimensional / Q000379:methods*; D016014:Linear Models; D008198:Lymph Nodes / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D018655:Lymphocyte Count; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D013601:T-Lymphocytes / Q000378:metabolism; D013950:Thymus Gland / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D014054:Tomography / Q000379:methods*
D049452:Green Fluorescent Proteins