In Vivo Imaging of Retinal Microglia in a Mouse Model of Glaucoma

Take an anesthetized transgenic mouse with glaucoma, a condition that damages the optic nerve and leads to vision loss.

The microglia, resident immune cells in the eye's retina, express a fluorophore-tagged protein for visualization.

Resting microglia display a ramified morphology with branched projections. Glaucoma-induced nerve damage activates microglia, which adopt an amoeboid shape with fewer projections.

Place the mouse on an ophthalmoscope platform and align the objective lens with one eye.

The eyes are covered with contact lenses to minimize dryness, and the pupils are dilated to expand the imaging field.

Visualize the retina using infrared illumination, which reduces tissue damage.

Identify the optic nerve head, where retinal ganglion cell axons converge to form the nerve.

Utilize retinal blood vessels as landmarks to establish the focal plane.

Switch to fluorescence mode to image the microglia, which appear as brightly fluorescent spots, and evaluate the presence of activated microglia comprising enlarged cell bodies and reduced branching complexity.