Immune System Induction of Nerve Growth Factor in an Animal Model of Multiple Sclerosis: Implications in Re-Myelination and Myelin Repair.

Nerve growth factor (NGF) expression is augmented during neuroinflammation. However, its function in the dorsal root ganglia (DRG) and spinal cord (SC) during experimental autoimmune encephalomyelitis (EAE), the inflammatory model of Multiple Sclerosis, is indistinct. Thus, the role of antigenically induced NGF in Lewis rats under a state of EAE was considered. NGF mRNA and protein expression were highly increased in DRG and SC tissues in animals with EAE. Between 18 and 24 days post induction (dpi), NGF mRNA and protein were elevated in the DRG, correlating with neurological recovery. In the SC, an increase in NGF protein at 12 dpi was, in contrast, preceded by neurological recovery. NGF mRNA expression became elevated in the SC at 15 dpi at the onset of neurological improvement and amelioration of EAE. This study revealed that antigenic induction of the 25 kDa pro-NGF isoform is associated with the disease course of EAE. Our findings suggest the induction of NGF represents an adaptive response against immune-mediated neuroinflammation in the DRG and SC that likely contributes to the EAE attenuation.