Biomedical Research

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Surgical model for ocular ischemic syndrome in mice

Background: To better understand the pathogenesis of Ocular Ischemic Syndrome (OIS), several animal models were established last decades. Our purpose is to characterize the functional and morphologic changes in a murine model of OIS caused by Bilateral Internal Carotid Artery Occlusion (BICAO).

Methods: Adult mice were submitted to BICAO or sham surgery. Changes in ocular blood flow and retinal circulation after surgery were evaluated by MRA to ensure the retinal blood flow occlusion. The retinal hypoperfusion was demonstrated 7 d after BICAO by both ocular fundus photography and fluorescein angiography. The OCT images were taken to measure the thicknesses of the various retinal layers, and then eyes were enucleated and embedded in paraffin for morphological studies.

Results: MRA images showed that the ligation of both internal carotid arteries significantly reduced ocular blood flow and narrowed the blood vessels. BICAO for 7 d was explored by both ocular fundus photography and fluorescein angiography finding that the retinal hypoperfusion persisted in the mice of BICAO group. The total retinal thickness and retinal ganglion cell density decreased compared with Sham group. However, no changes were evident in IPL layer in BICAO group, which was in agreement with the results obtained from OCT images.

Conclusion: We successfully visualized the occlusion of blood flow after the BICAO by MRA, and angiography could also demonstrate that BICAO for 7 d was sufficient to maintain the retinal ischemia and induce the morphological changes. We suggest that this protocol might be used as a mouse model for OIS in the future.

Author(s): Yu Ling, Zhiyong Fu, Yanling Wang