Behaviour of CD11b-Positive Cells in an Animal Model of Laser-Induced Choroidal Neovascularisation.

BACKGROUND/AIM: Immune cells, e.g. microglial cells of the retina, appear to be involved in pathological processes in neovascular age-related macular degeneration. Therefore, the purpose of this study was to immunohistochemically check the expression of various factors and cytokines by CD11b-positive (CD11b+) immune cells in an animal model of choroidal neovascularisation (CNV). METHODS: We used the animal model of laser-induced CNV in mice. Eyes were isolated at 1, 4, 7, and 14 days after laser treatment. Cryosections were prepared and checked immunohistochemically for the presence of different growth factors and cytokines on microglial cells and other immune cells identified by CD11b immunoreactivity. RESULTS: We found that the number of CD11b+ cells at the laser spots increased dramatically 4 days after laser treatment, the majority of them entering the laser spot most probably by migration. CD11b+ cells in the laser spot were positive for a variety of pro-angiogenic factors, such as PDGF-ß, FGF-1, FGF-2, and TGF-ß1. They were also positive for some inflammatory cytokines, in particular TNF-α, IL-6, and CXCL1. In non-treated retinas, CD11b+ cells showed almost no immunoreactivity for these proteins. CONCLUSION: Microglial cells, macrophages, and other CD11b+ cells may promote the neovascularisation in the laser spot and show a moderate inflammatory behaviour. Immunoreactivity for most of these molecules was found to decrease during the time of observation. Modulation of immune cell activity may thus be a tool to reduce the extent of CNV.

OCT angiography in the mouse: A novel evaluation method for vascular pathologies of the mouse retina.

PURPOSE: To investigate the application of optical coherence tomography (OCT) angiography in the retinas of healthy mice and to evaluate choroidal neovascularization (CNV) in a mouse model of laser-induced CNV. METHODS: C57BL/6J mice aged 18-25 weeks were examined using the spectral-domain optical coherence tomography device RTVue XR Avanti (Optovue, Inc, Fremont, California, USA). Blood flow in different retinal layers was detected using the split-spectrum amplitude-decorrelation angiography algorithm. Fluorescein angiography (FA) images were obtained using the Heidelberg Spectralis device (Heidelberg, Germany). RESULTS: Using the RTVue XR Avanti, we were able to obtain high-quality OCT angiography images of normal vasculature in the superficial, deep capillary and choriocapillary layers in laser-treated mice and untreated controls. Whereas no blood flow was detectable in the outer retina of untreated mice, blood flow and hence neovascular vessels were found in laser-treated mice. CONCLUSIONS: OCT angiography can clearly visualize the normal vascular plexus in the different retinal layers in the mouse retina and choroid. With OCT angiography, it is possible to verify the choroidal neovascularization induced by laser treatment. Thus, OCT angiography is a helpful imaging tool for non-invasive, in vivo evaluation of laser-induced CNV in the mouse.