Presence of nerve growth factor and TrkA expression in the SVZ of EAE rats: evidence for a possible functional significance

Nerve growth factor (NGF) is a well-characterized neurotrophic factor that plays a crucial role during development in the growth, differentiation, and maintenance of brain neurons as well as in the reparative response of the adult brain to neuronal damage. Recent studies have shown that acute axonal loss occurs in multiple sclerosis (MS) and its animal model, experimental allergic encephalomyelitis (EAE), and that NGF suppresses clinical symptoms of EAE in nonhuman primates. Aim of the present study was to investigate the role of NGF in the regenerative response of the adult brain to neuronal damage occurring in EAE. Using EAE rats, we have found that exogenous NGF injection and NGF deprivation (NGF autoimmunization) can act on growth and differentiation of brain precursor cells in the subventricular zone (SVZ) of EAE rats. Moreover, NGF administration in brain of EAE rats stimulates the expression of early neuronal markers on proliferating precursor cells of the SVZ. The data obtained demonstrated that NGF and its antibody affect bromodeoxyuridine (BrdU) incorporation and NGF receptor expression by SVZ progenitor cells in the brain of EAE rats.