Progesterone attenuates neurological behavioral deficits of experimental autoimmune encephalomyelitis through remyelination with nucleus-sublocalized Olig1 protein

Multiple sclerosis (MS) is the most common demyelination disease of central nervous system (CNS). The deterioration of the disease is characterized by the axonal loss with defective remyelination. Progesterone can promote the remyelination, but whether it exerts beneficial effect on treatment of MS still remains unclear. Olig1 protein is a key regulator in the remyelination, when the intracellular sublocalization plays an import role too. We observed the effect of progesterone on experimental autoimmune encephalomyelitis (EAE) in rats by injecting the progesterone after the neurological behavioral deficits were shown up. The results showed no continuous increase of the nervous function score from day 10 after injection (p < 0.05). Electron microscopy and LFB staining found prominent increase of OD value of normal myelin in the brain from day 6 after injection (p < 0.05). Olig1 protein was localized almost completely in the cytoplasm of Olig1-positive cells from normal rats’ brain. In EAE rats, the Olig1 protein has been translocated to the nucleus of 32.17% of Olig1-positive cells, which was increased to 68.52% after injection with progesterone at day 6 after injection (p < 0.01). The results indicate that the progesterone is beneficial to attenuating neurological behavioral deficits, for it can promote more successful remyelination of EAE with aid of the nucleus-sublocalized Olig1 protein.