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Updated: Jul 18, 2026
Induction of Acute Ischemic Stroke in Mice Using the Distal Middle Artery Occlusion Technique
Published on: December 15, 2023
Microglia and macrophages express tumor necrosis factor receptor p75 following middle cerebral artery occlusion in
K L Lambertsen1, B H Clausen, C Fenger
1Medical Biotechnology Center, Winsloewparken 25, University of Southern Denmark, Odense, DK-5000, Denmark. klambertsen@health.sdu.dk
Abstract:
The proinflammatory and potential neurotoxic cytokine tumor necrosis factor (TNF) is produced by activated CNS resident microglia and infiltrating blood-borne macrophages in infarct and peri-infarct areas following induction of focal cerebral ischemia. Here, we investigated the expression of the TNF receptors, TNF-p55R and TNF-p75R, from 1 to 10 days following permanent occlusion of the middle cerebral artery in mice. Using quantitative polymerase chain reaction (PCR), we observed that the relative level of TNF-p55R mRNA was significantly increased at 1-2 days and TNF-p75R mRNA was significantly increased at 1-10 days following arterial occlusion, reaching peak values at 5 days, when microglial-macrophage CD11b mRNA expression was also increased. In comparison, the relative level of TNF mRNA was significantly increased from 1 to 5 days, with peak levels 1 day after arterial occlusion. In situ hybridization revealed mRNA expression of both receptors in predominantly microglial- and macrophage-like cells in the peri-infarct and subsequently in the infarct, and being most marked from 1 to 5 days. Using green fluorescent protein-bone marrow chimeric mice, we confirmed that TNF-p75R was expressed in resident microglia and blood-borne macrophages located in the peri-infarct and infarct 1 and 5 days after arterial occlusion, which was supported by Western blotting. The data show that increased expression of the TNF-p75 receptor following induction of focal cerebral ischemia in mice can be attributed to expression in activated microglial cells and blood-borne macrophages.
Insights
Tumor necrosis factor (TNF) receptors are upregulated in the brain after stroke. This study shows increased TNF-p75 receptor expression in microglia and macrophages following focal cerebral ischemia in mice.
Area of Science:
- Neuroscience
- Immunology
- Molecular Biology
Background:
- Tumor necrosis factor (TNF) is a key inflammatory cytokine implicated in neurotoxicity following focal cerebral ischemia.
- Activated microglia and infiltrating macrophages in the brain produce TNF in infarct and peri-infarct regions.
Purpose of the Study:
- To investigate the expression patterns of TNF receptors (TNF-p55R and TNF-p75R) in the mouse brain following induced focal cerebral ischemia.
- To determine the cellular sources of TNF receptor expression in the ischemic brain.
Main Methods:
- Quantitative polymerase chain reaction (PCR) to measure mRNA levels of TNF, TNF-p55R, TNF-p75R, and CD11b.
- In situ hybridization to localize mRNA expression of TNF receptors.
- Green fluorescent protein-bone marrow chimeric mice and Western blotting to confirm protein expression and cellular localization.
Main Results:
- TNF-p55R mRNA levels increased at 1-2 days post-ischemia, while TNF-p75R mRNA levels increased from 1 to 10 days, peaking at 5 days.
- TNF mRNA levels were elevated from 1 to 5 days, with peak expression at 1 day.
- In situ hybridization and chimeric mouse studies confirmed TNF-p75R expression in microglia and macrophages within the infarct and peri-infarct areas.
Conclusions:
- Focal cerebral ischemia induces significant upregulation of TNF-p55R and TNF-p75R mRNA in the mouse brain.
- The increased expression of TNF-p75 receptor following cerebral ischemia is primarily attributed to activated microglia and blood-borne macrophages.
