BACKGROUND:Previous studies have focused on the correlation between Nogo-A expression and multiple sclerosis or between Nogo-A receptor (NgR) expression and multiple sclerosis in the central nervous system. Expression patterns of Nogo-A and NgR remain poorly understood in rat models of experimental autoimmune encephalomyelitis (EAE).OBJECTIVE:To observe dynamic changes in Nogo-A and NgR protein expression, and to verify the correlation between Nogo-A and NgR protein, as well as expression patterns at various time points, in periventricular tissue of EAE rats.DESIGN, TIME AND SETrlNG:A neuroimmunological, randomized, controlled experiment was performed at the Clinical Institute of Hunan People's Hospital of China from September to November 2008.MATERIALS:Immunohistochemistry (streptavidin-biotin-peroxidase complex method) kit was purchased from Boster, China.METHODS:A total of 60 female, Wistar rats, aged 6-8 weeks, ware randomly assigned to EAE and control groups (n = 30, respectively). Guinea pig spinal cord homogenate, self-made complete Freund's adjuvant (0.2 mL/100 g), and pertussis vaccine (0.2 mL) were subcutaneously injected into the hindlimb foot pad of rats from the EAE group to create rat models of EAE. Complete Freund's adjuvant (0.2 mL) was infused into rats from the control group.MAIN OUTCOME MEASURES:Nogo-A and NgR protein expression was determined in periventricular white matter using immunohistochemical methods. Neurological scores ware determined in all rats.RESULTS:Rats from the EAE group developed acute-onset EAE following immunization. The pathogenetic symptoms reached a peak on day 15, and neurological scores ware also greatest at this time point. Neurological scores decreased with recovery of the illness. Nogo-A was shown to be expressed in neuronal cells and oligodendrocytes, and expression increased 11 days after immunization (P < 0.01), decreased by day 13 (P < 0.01), and then increased again by day 15. Nogo-A expression remained greater in the EAE group compared with the control group at day 30 (P < 0.01). In the EAE group, NgR protein was primarily expressed on the surface of neuronal bodies and axons. NgR expression increased 13-18 days after immunization (P < 0.01 or P < 0.05).CONCLUSION:Nogo-A and NgR protein expression altered with disease course in periventdcular white matter of EAE rats. Results suggested that Nogo-A and NgR were involved in EAE occurrence.