Neuroprotective Effect And Mechanism Of Astragalus Injection On Multiple Sclerosis

Objective:To investigate the neuroprotective effect and mechanism of astragalus injection on Wistar rats of experimental autoimmune encephalomyelitis (EAE),which is the classic animal model for multiple sclerosis.Methods:1. The animal model was established in Wistar rats by immunizing rats with guinea pig spinal cord homogenate(GPSCH),complete Freund's adjuvant (CFA), and pertussis vaccine(PV). These animals were examined daily for the weight and clinical signs. Brain, spinal cord were dissected, and the pathological changes were observed with histopathological , immunopathological and electron microscope techniques. We evaluated the animal model of EAE by the above indexes.2. Wistar rats were randomly divided into three groups: control group, EAE group and treatment group. The animals of treatment group were injected peritoneally with astragalus injection(4ml/kg/d), while the EAE group were injected with physiological salt solution(4ml/kg/d), starting from the 1st day after immunization to the day rats were sacrificed. The severity of EAE was scored on a scale according to the signs and symptoms. All the animals were sacrificed at the 16th day. Brain, spinal cord were dissected, and the pathological changes were observed histopathologically and immunopathologically. CD4+/CD8+ of peripheral blood was detected with flow cytometric analysis, and some cytokines were detected by ELISA.Results:1.We successfully established an experimental autoimmune encephalomyelitis model in Wistar rats by immunizing rats with guinea pig spinal cord homogenate(GPSCH). The first neurological manifestations appeared at the 8th day after immunization, and the animals began to recover at about 8 days after the onset. The classic perivascular infiltration and demyelinating can be found in the CNS of EAE rat.2. Our results revealed that CD4+ T cells were activated in the starting procedure, and a great quantity of free radical and inflammatory factors such as IL-17, IL-23, MCP-1, ICAM-1 generated. The aboving changes could lead to demyelination in nerve tissue. After intervention by astragalus injection, the concentration of free radical in the serum and the content in central nervous system of IL-17,IL-23, MCP-1, ICAM-1 reduced , and the apoptosis increased in the detected tissues, all the results showed statistically significant differences with the EAE groups(P<0.01). The clinical manifestation and the histological change of EAE were significant (P<0.01), too. It was implied that astragalus injection could cut down the contents of inflammatory factors selectivity , relieve the damage of free radical, and increase the apoptosis, so that lessen the lesions in nerve tissue, which may be parts of the important mechanisms of astragalus injection for protecting neurocyte and treating MS.Conclusion:1. An experimental autoimmune encephalomyelitis model was successfully established in Wistar rats with guinea pig spinal cord homogenate(GPSCH).2. Astragalus injection could cut down the contents of inflammatory factors, relieve the damage of free radical,and increase the apoptosis, so that lessen the lesions in nerve tissue, protect neurocyte in MS.