| Objective:This study was design to explore the effects of a new immunosuppressive agents Fingolimod (FTY720) on induced experimental autoimmune encephalomyelitis (EAE) in Wistar rats, and discuss the underlying immuno-regulatory mechanism of EAE by investigating the apoptosis related proteins of BCL-2 and FAS.Methods:The animal model was established in female Wistar rats by immunizing rats with guinea pig spinal cord homogenate (GPSCH) complete freund's adguvant (CFA) and pertussis vaccine (PV). Seventy wistar rats were randomly divided into seven groups, from group A to group G:ten rats in normal group (group A), ten rats in EAE group (group B) different doses FTY720 group (group C, group D, group E, group F) and Prednisone group (group G), Rats were fed with FTY720 in different doses FTY720 group, while prednisone group were fed with prednisone, starting from the immunization to the day rats were sacrificed. All the animals were sacrificed at the 18th day. The severity of EAE was scored on a scale 0-5 according to the signs and symptoms. Hematoxylin-eosin staining and Luxol Fast Blue myelin staining were performed on the sections of rats'brain. The number of inflammation focus in the central nervous system (CNS) was counted under the optical microscope. The expressions of BCL-2 and FAS in brain tissue were detected by immunohistochemistry technique. Experimental results were analyzed with SPSS 17.0.Results:1. No disease phenotype was observed in group A. Comparing to group B, group C had degraded in eclipse period, weight loss and neurological deficit scores (p<0.05) but had no difference in morbility; while group D, group E, group F and group G's rats appeared decreased in morbility, eclipse period, weight loss and neurological deficit scores (p<0.05).Comparing to group C, the group D, group E, group F and group G's rats had degraded in morbility, eclipse period, weight loss and neurological deficit scores(p<0.05). There was no difference between group D, group E and group G's rats in morbility, weight loss and neurological deficit scores (p>0.05),while group F had degraded in morbility, eclipse period Comparred with group G (p<0.05).2.The CNS tissue's hematoxylin-eosin (HE) staining histopathology results of group B's rats indicated that CNS already had inflammation while no change in group A. Comparing to group B, the extent and amount of the inflammation focus decreased in the group C, group D,group E, group F and group G (p<0.05). Comparing to group C, the extent and amount of the inflammation focus decreased in the group D, group E, group F and group G (p<0.05). Comparing to group G, group D, group E's rats have no different in the extent and amount of the inflammation (p>0.05),but the extent and amount of the inflammation focus decreased in the group F (p<0.05). Luxol fast bule-Cresyl fast violet myelin staining indicated no demyelination in group A. In group B the demyelination lesions were the most serious. Dispersive demyelination focuses could be seen casually in groups C to groups G.3. Immunohistochemistry and image analysis results of each group rats indicated that the CNS expression level of BCL-2 and FAS had increased in the group B comparing with group A(p<0.05). Comparing to group B, group C, group D,group E, group F and group G's rats had higher level of BCL-2 and FAS (p<0.05). Comparing to group C, group D, group E, group F and group G's level of BCL-2 and FAS decreased (p<0.05). Comparing to group G, group D and group E had no difference in level of BCL-2 and FAS (p>0.05), but group F's level of BCL-2 and FAS decreased (p<0.05)Conclusion:1. FTY720 has amelioration effect on EAE rats and the effects were probablly in dose-dependent fashion.2. One of the mechanisms related to FTY720's amelioration effect on EAE is to down-regulation the level of BCL-2 in the CNS, to reduce the inflammation of CNS.3. One of the mechanisms related to the pathogenesis of EAE is to up-regulation the level of FAS in the CNS. |
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