To evaluate the expression patterns of F4/80 and nestin in the ciliary body and the optic nerve following N-methyl-N-nitrosourea (NMU)-induced retinal degeneration in adult mice.

After intraperitoneal injection of MNU (60 mg/kg) in adult mice, the eyes were enucleated at 2, 4, 7 and 30 days. Hematoxylin and eosin (H&E) stain, terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) stain and immunohistochemical stains of F/80 and nestin were performed.

After MNU treatment, the photoreceptors were destroyed by cell apoptosis. According to immunohistochemistry, F4/80 and nestin were not co-expressed in the control group, but F4/80 was expressed within the ciliary body and optic nerve in the MNU-treated group; the expression of nestin also increased. In the outer nuclear layer, F4/80 and nestin co-expressing cells were observed.

In response to retinal damage, the F4/80 and nestin co-expressing cells migrated to the retina from the ciliary body and optic nerve and were activated.