The Expression Of IL-27,IL-17 And IL-10 In Experimental Allergic Neuritis And The Interfering Effect Of IL-27 For EAN

Objective Guillain-Barre' syndrome(GBS) is a common autoimmunedisease,characterized by inflammation and demyelination of the peripheral nervous system(PNS).Now the pathogenesis of GBS remains poorly understood.Experimental allergic neuritis(EAN) is a T cell mediated animal model of GBS and a prototype disease for studies of mechanisms involved in CD4⁺T cell mediated autoimmunity. Cytokine-mediated immunity plays a crucial role in pathogenesis of various diseases including autoimmune disease.In 2002,interleukin 27 was identified,which along with interleukin 23 belongs to the interleukin 12 cytokine family.Initial studies on the biology of IL-27 provided evidence of a role for this cytokine in the initiation of Th1 responses; however,subsequent work using models of pathogen-induced and autoimmune inflammation have indicated that IL-27 has broad inhibitory effects on Th1 and Th17 subsets of T cells,therefore,it can be applied in many experimental autoimmune diseases.This experiment make use of reverse transcription-polymerase chain(RT-PCR) to observe the dynamic changes of mRNAof the two IL-27 subunit P28 and EBI3,IL-17,IL-10in blood of EAN rats and the changes for response to IL-27.By this study we will explore the interfering effect of IL-27 for EAN and discuss the role of IL-17 and IL-10 in the pathomechanism of the EAN.And this study will give us new treatment idea for GBS and other autoimmune diseases.Methods1.Grouping:104 Male 6-8-wk-old Lewis rat were derided into five randomized groups,which were called NS control group,CFA control group,EAN group,IL-27 group and NS intervention control group.2.Building EAN model:Lewis rats were immunized by injection into both hind footpads with altogether 200μl emulsion containing 100μg the component of PNS myelin sheath protein P2_53-78aa peptide emulsified in 100μl salin and 100μl Freund' s complete adjuvant,and,5 days post immunization,IL-27 were injected into rats subcutaneously.3.Observe the clinical signs of rats and pathological changes in the sciatic nerves of rats.The rats in the groups of immunized and control were sacrificed at defined intervals(day7,day16,day24, day33) after being immunized.Embed sciatic to make paraffin section and stain it by HE stain and Weil's stain to observe the extent of the inflammatory infiltrating and the demyelination.4.The expression of mRNA of IL-27 P28 and EBI3,IL-17,IL-10were detected by RT-PCR dynamically which come from peripheral blood,spleens,siatic nerves and lymphonodes of experimental animals.Results:EAN group got the peak of clinical score at the 16d p.i,and the clinical manifestation ameliorated obviously at 33d.p.i.The mRNA expression of IL-27 P28 got the peak at the 24d.p.i,IL-27 EBI3,IL-17 got the peak at the 16d.p.i,then reduced gradually,but at the 33d.p.i,it was still higher than that of the CFA and NS control group(P＜0.01),there was significant difference among the four time point,(P＜0.01).Firstly,the mRNA expression of IL-10 was low,and it got the peak at the 24d.p.i.The clinical situation of EAN+IL-27 group was ameliorated significantly compared with EAN group and EAN+NA group,and the extent of the inflammatory infiltrating and the demyelination in the sciatic nerve lessen significantly.The mRNA expression of IL-17was lower than EAN group and EAN+NA group at the 16d,24d,33d.p.i(P＜0.01) while the mRNA expression of IL-27 P28,IL-27 EBI3,IL-10 was higher than EAN group and EAN+NA group at the three time points(P＜0.01).Conclusions:1.IL-27 can suppress the development of EAN in Lewis rats.2.The secretion of IL-17 may contribute to the onset and development of the EAN,while the secretion of IL-10 may ameliorate the EAN.3.IL-27 possibly inhibits inflammatory response by inhibiting the secretion of IL-17 and promoting the secretion of IL-10.