Anti-NGF-antibody administration as collyrium reduces the presence of NGF and enhances the expression of VEGF in the retina, lacrimal gland and hippocampus

In the present study we investigated the effects of eye anti-nerve growth factor (NGF)-antibody (ANA) application on the retina, lacrimal gland, and brain cells of aged mice. Mice were treated three times daily for three consecutive weeks with ANA or with pre-immune IgG. Then mice were sacrificed and retina and brain used for biochemical and immunohistochemical studies. Eye ANA application reduced the level of NGF and enhanced the expression of VEGF in all these three tissues. Moreover, ANA treatment reduced the number of basal forebrain neurons expressing choline acetyltransferase, ChAT, a cholinergic enzyme regulated by NGF. This observation is in line with previous reports showing that biologically active compounds, including high molecular weight proteins such as NGF and ANA, can be delivered by an alternative ocular route into the brain, allowing to understand the role of NGF and VEGF in retinal and brain cell degeneration and regeneration.