RESUMO
In order to investigate the role of heme oxygenase-1 (HO-1) in the molecular mechanism of experimental allergic encephalomyelitis (EAE), which was induced by guinea pig spinal cord homogenate + complete freund adjuvant on Wistar rats, we observed the gene of HO-1 and its protein expression with reverse transcriptase polymerase chain reaction(RT-PCR) and immunohistochemistry 1, 7, 14, and 21 d after EAE induction in rats. The relationship between HO-1 and the symptoms of EAE was also observed. The results showed that the levels of HO-1 mRNA and its protein expression were very low in the brains of the control group, whereas they were enhanced gradually with pathological course in the brain and onsets of symptoms, signs of EAE. On day 7, the level of HO-1 mRNA reached the peak, but the expression level of HO-1 protein in the brains reached the peak on day 14. The immunoreactive cells of HO-1 were mainly located at the choroid plexuses and subfornical organ (SFO), as well as in regions around the "sleeve-like" lesion foci, all of which were coincident with the locations of lesions of EAE. The levels of HO-1 mRNA and its protein expression were lowered gradually on day 21, which were in parallel with the severities of symptoms and signs of EAE. After a specific inhibitor of HO-1, Snpp-9, was applied, both of the symptoms and pathological lesions of EAE in the rat brains were mitigated markedly. Therefore, these results may suggest that the dynamic changes of HO-1 mRNA and its protein expression are in parallel with the changes of symptoms and pathological lesions of EAE in the brain. In conclusion, the levels of HO-1 mRNA and its protein expression in brains may play an important role in the pathogenesis of EAE, and application of inhibitors of HO-1 may be one of the potential therapeutic ways for the prevention and treatment of EAE.