Corneal healing through apoptosis

The Arthus type allergic reaction in the cornea is characterised by inflammatory cell infiltration and marked neovascularisation. This gradually disappears during the healing stages through mechanisms that are not yet elucidated but which are essential to preserve vision. In the May British Journal of Ophtalomology, Noriko Ozaki and colleagues from the Nippon Medical School, Tokyo show that regression of the Arthus reaction in the cornea occurs via apoptosis.

Ozaki et al injected bovine serum albumin into the central corneal stroma of rabbits to induce an Arthus type allergic reaction. The corneas were analysed by both light microscopy using in situ TdT-dUTP nick end labelling (TUNEL) and electron microscopy. They found that while the inflammation and neovascularisation gradually disappeared, the numbers of microvessel endothelial cells and infiltrated inflammatory cells undergoing apoptosis increased. Apoptotic bodies were taken up by macrophages as well as myofibroblasts derived presumably from transformation of migrated keratocytes...