Related Experiment Video
Updated: Jun 13, 2026
In Vivo Imaging of Cx3cr1gfp/gfp Reporter Mice with Spectral-domain Optical Coherence Tomography and Scanning Laser Ophthalmoscopy
Published on: November 11, 2017
Conditions of retinal glial and inflammatory cell activation after irradiation in a GFP-chimeric mouse model
Philipp S Müther1, Irina Semkova, Kristina Schmidt
1Department of Ophthalmology, University of Düsseldorf, Düsseldorf, Germany.
Purpose:
Microglia cells have been associated with immunologic defense and repair. The course of retinal disease after lethal irradiation for bone marrow depletion and substitution was evaluated with respect to macrophage and microglial involvement.
Methods:
Lethal irradiation in C57BL/6 mice was conducted with a low-voltage radiation unit. The animals were randomized to shielded or unshielded radiation and subsequently received transplants of GFP+ bone marrow cells (beta-actin promoter). The GFP transformation rate was analyzed by flow cytometry. GFP+ cells in the retina were examined for co-localization with macrophage and dendritic cell markers at various time points between 1 and 7 months after irradiation. Clodronate liposomes were used to investigate the fate of migrated and residential microglia cells. Pathologic angiogenesis was investigated in laser-induced choroidal neovascularization (CNV) after unshielded and shielded irradiation.
Results:
Flow cytometry revealed average transformation rates of 78.2% in unshielded and 64.1% in shielded group. Four weeks after transplantation, perfused flat mounts were virtually free of extravasal GFP+ cells in both groups, whereas 4 months after irradiation, cluster cell infiltrations, preferentially in the peripheral retina, became apparent exclusively in the unshielded group. Cell morphology ranged from oval, to a few extensions, to dendritiform with long-branched extensions. Clodronate treatment resulted in a reduction of GFP+ cells in the retinal tissue when applied 3 months after unshielded irradiation. Although GFP+ cells accumulated in the choroidal scar after laser treatment, in both the shielded and unshielded groups, GFP+ cells in the overlying retina were restricted to the unshielded group.
Conclusions:
Approximately 3 months after lethal full-body irradiation including the eye, bone marrow-derived leukocytes exhibit a wound-healing reaction, and unlike physiological turnover, infiltrate the retina and form microglial cells.
Insights
Bone marrow cells can become microglia in the retina after lethal irradiation. These cells infiltrate the retina, exhibiting a wound-healing response rather than normal turnover.
Area of Science:
- Immunology
- Ophthalmology
- Cell Biology
Background:
- Microglia cells are crucial for immune defense and repair in the retina.
- Retinal disease progression after bone marrow transplantation involves immune cell dynamics.
Purpose of the Study:
- To evaluate the role of macrophages and microglia in retinal disease following lethal irradiation and bone marrow transplantation.
- To investigate the infiltration and differentiation of bone marrow-derived cells in the retina post-irradiation.
Main Methods:
- Mice underwent lethal irradiation and bone marrow transplantation with GFP+ cells.
- Flow cytometry analyzed GFP+ cell transformation rates.
- Retinal tissues were examined for GFP+ cells, macrophage/dendritic cell markers, and microglia morphology.
- Clodronate liposomes assessed the fate of microglia.
- Laser-induced choroidal neovascularization (CNV) models evaluated angiogenesis.
Main Results:
- Significant GFP+ cell transformation rates were observed in both shielded and unshielded groups.
- GFP+ cells infiltrated the peripheral retina in the unshielded group around 4 months post-irradiation.
- Clodronate treatment reduced GFP+ cells in the retina.
- GFP+ cells were restricted to the retina in the unshielded group after laser-induced CNV.
Conclusions:
- Bone marrow-derived leukocytes infiltrate the retina approximately 3 months after lethal irradiation.
- These infiltrating cells exhibit wound-healing characteristics and differentiate into microglial cells.
- This process differs from physiological microglial turnover.
