The Dynamic Expression Of P-p38MAPK In Spinal Cord Lumbar Enlargement Tissues Of Experimental Autoimmune Encephalomyelitis Mice And The Mechanism Underlying Protective Effect Of SB203580

Objective:Multiple sclerosis(MS), the most common disabling neurologic disease of young adults, is a chronic autoimmune inflammatory disease of the central nervous system(CNS). Like most autoimmune diseases, it has a complex and poorly understood etiology whereby environmental factors acting upon a susceptible genetic background culminate in disease. Pathogenic T cell responses against myelin antigens expressed in the CNS lead to lesion formation that is characterized by focal demyelination, axon loss, and Gliosis.While CD4 T cells, including Th1 cells, Th2 cells and Th17 cells, initiate the inflammatory cascade in the CNS, Th17 cells characterized as the secretion of IL-17 are thought to play an important role in mediating the tissue destruction and pathology. p38 MAPK, a significant member of MAPK family emphasized by scientists recent years due to its role in regulating Th17 cells is primarily activated by cell stress and inflammatory insults.Through examine the expression of p38 MAPK, p-p38 MAPK and IL-17 in lumbar enlargement of mice in different groups, namely control group, EAE 13 d group, EAE 20 d group, EAE 30 d group, we intend to explore the possible effect of p38 MAPK in mechanisms of experimental autoimmune encephalomyelitis(EAE) onset. Moreover, SB203580 is applied as a kind of treatment and after the application of SB203580 we observe the morbidity, severity, the weight loss of mice in peak EAE and examine the expression of p38 MAPK, p-p38 MAPK,IL-17 in lumbar enlargement of mice from SB203580 group in order to explore the possible mechanism in protective effect of SB203580 in detail. As a result, we design and implement this experiment.Methods: Eighty C57BL/6 mice immuned with MOG35-55 were randomly divided into five groups: control group, EAE 13 d group, EAE 20 d group, EAE 30 d group and SB203580 group. There are sixteen mice in each group. The day on which the mice were immunized was recorded as Day 0. The SB203580-treated mice received the SB203580(0.2mg/kg) by peritoneal injection every day from Day 1, mice in other groups received equal volume of DMSO, the solotion of SB203580 every day from Day 1. The morbidity of EAE, weight, and clinical signs were observed two times a day. The pathological changes in lumbar enlargement of spinal cord were observed by HE staining and LFB staining. The expression of p38 MAPK, p-p38 MAPK, and IL-17 was observed by western blot technology.Results:1 No mice in control group develops EAE. Compared to EAE groups, the mobility, weight loss and mean clinical score of the mice in SB203580 group were significantly lower(P<0.05).2 In the early onset of EAE(EAE 13 d group), peak EAE(EAE 20 d group) and relieved EAE(EAE 30 d group), pathological analysis(HE staining and LFB staining) demonstrated a significantly increased numbers of inflammation cells and grave demyelination condition in the lumbar enlargement of spinal cord of mice, compared to the control group. Moreover, the inflammation cells and demyelination condition in the lumbar enlargement of spinal cord of mice from SB203580 group decreased significantly, compared with that of mice from EAE 20 d group.3 Among control group, EAE 13 d group, EAE 20 d group, EAE 30 d group: There is no statistical difference of the expression of p38 MAPK in each groups. Compared with control group and EAE 13 d group, the expression of p-p38 MAPK in EAE 20 d group and EAE 30 d group increased significantly(P<0.05). Additionally, the expression of IL-17 in EAE 20 d group increased, compared with other groups(P<0.05).4 Among control group, EAE 20 d group, SB203580 group: There is no statistical difference of the expression of p38 MAPK in each groups. Compared with EAE 20 d group, the expression of p-p38 MAPK and IL-17 in SB203580 group decreased significantly(P<0.05).Conclusions:1 p38 MAPK play a important role in EAE through Th17 cells mediated- inflammatory response mechanism.2 SB203580 can efficiently decrease the mobility, the level of weight loss, the mean clinical score, the numbers of inflammation cells and relieve the demyelination condition of mice in EAE.3 SB203580 protective effect may derive from the suppression of Phosphorylation of p38 MAPK and futher decrease the Th17 cells mediated- inflammatory response in EAE.