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Updated: Sep 30, 2026
Depletion and Reconstitution of Macrophages in Mice
Published on: August 1, 2012
[Macrophage depletion inhibits leukocyte recruitment in experimental melanin-induced uveitis (EMIU)]
1Zentrum der Augenheilkunde, Johann Wolfgang Goethe-Universität, Frankfurt am Main. j.puchta@gmx.de
Background:
To study the role of macrophages in experimental melanin-induced uveitis (EMIU), we used the method of intravital microscopy to analyse changes in leukocyte adhesion to iris venules of live rats with EMIU after pretreatment with liposomal clodronate.
Materials And Methods:
EMIU was induced in Lewis rats (n = 48) by intraperitoneal immunisation with bovine crude melanosomes emulsified in complete Freund's adjuvant (CFA) and pertussis toxin (PTX). Control animals received CFA and PTX only (n = 12) or no injection (n = 6). Animals were treated with liposomal clodronate (DMDP-lip) or empty liposomes on days -2, +1, 4, 6 and 8. Using IVM, postcapillary iris venules of rats were examined to quantify leukocyte rolling and firm adhesion to the vascular endothelium.
Results:
Depletion of macrophages caused a decreased percentage of rolling leukocytes on day 8 (2 +/- 1.1% vs 15.2 +/- 1.6%, DMDP-lip vs EMIU, mean +/- SEM, ANOVA, p < 0.05) and day 10 (2.6 +/- 0.3% vs 14.2 +/- 1.6%). A significant decline in the number of firmly adherent leukocytes was detected on days 8 and 10 (88 +/- 13/mm2 vs 175 +/- 18/mm2 and 129 +/- 13/mm2 vs 372 +/- 31/mm2, DMDP-lip vs EMIU). Treatment with empty liposomes showed no changes in leukocyte firm adhesion.
Conclusions:
Elimination of macrophages prevents the induction of EMIU. In autoimmune-mediated uveitis, macrophages play a crucial role in the initiation of leukocyte-endothelium interaction.
Insights
Macrophages are crucial in initiating experimental melanin-induced uveitis (EMIU). Eliminating these immune cells prevents EMIU by reducing leukocyte adhesion to blood vessels, highlighting their role in autoimmune eye inflammation.
Area of Science:
- Immunology
- Ophthalmology
- Cell Biology
Context:
- Experimental melanin-induced uveitis (EMIU) is an autoimmune condition affecting the eye.
- Macrophages are key immune cells implicated in inflammatory processes.
- Understanding leukocyte-endothelium interactions is vital for uveitis research.
Purpose:
- To investigate the role of macrophages in the pathogenesis of EMIU.
- To quantify the effect of macrophage depletion on leukocyte adhesion in EMIU using intravital microscopy (IVM).
Summary:
- Lewis rats were induced with EMIU and treated with liposomal clodronate to deplete macrophages.
- Intravital microscopy assessed leukocyte rolling and firm adhesion in iris venules.
- Macrophage depletion significantly reduced leukocyte rolling and firm adhesion compared to controls.
Impact:
- Macrophage elimination effectively prevents the induction of EMIU.
- This study demonstrates a critical role for macrophages in initiating leukocyte-endothelium interactions during autoimmune uveitis.
- Findings provide insights into potential therapeutic targets for autoimmune eye diseases.
