Effect Of CD40SiRNA On Th17Cells And IL-17and IL-23in Rats With Experimental Autoimmune Myocarditis

Objective Viral myocarditis is one of children’s common diseases. The severe outcomes of viral myocarditis include arrhythmias, development of dilated cardiomyopathy, heart failure, cardiogenic shock and sudden death. Although it’s pathogenesis is not clear, more and more researches demonstrates that autoimmune injury is the important reason of late myocarditis myocardial injury. Therefore we can explore the immune mechanism pathogenesis of viral myocarditis by establishing animal model of autoimmune myocarditis and simulating the late process of viral myocarditis. T helper type17(Thl7) cells are a distinct lineage of T cells found in recent years, they can produce the effector molecules IL-17, IL-21,and IL-22, The transcription factor ROR γt and ROR α induces Th17differentiation. They involve in the development of many kinds of autoimmune disease, such as systemic lupus erythematosus, multiple sclerosis, late viral hepatitis and so on. There is growing evidence that Th17lineage cells and its effector molecules IL-17are critical in myocarditis. Small interfering RNA(siRNA).also known as short interfering RNA or silencing RNA, generally contains20-25nucleotides. SiRNA mainly involves in the phenomenon of RNA interference, regulates gene expression n specifically. Gene silencing using small interfering RNA (siRNA) is a potent method of specifically knocking down molecular targets. Small interfering RNA is therapeutically promising, however, treatment of autoimmune myocarditis with siRNA has not been explored in vivo. The aim of this study was to evaluate therapeutic effects of CD40siRNA on inhibition of autoimmune myocarditis. The objective of this study is to investigate the effect of CD40siRNA on the pathologic changes and Th17cells of myocardium and IL-17、IL-23of serum in rats with experimental autoimmune myocarditis.Methods Forty6-8week old healthy male Lewis rats with body weight of185-210g were divided into EAM group, CD40siRNA group, siRNA group, and normal control group randomly, every group has ten rats. The rats in EAM group, CD40siRNA group and siRNA group were induced by immunization with cardiac C protein and completed Freund adjuvant in double foot pads. The rats in normal control group were injected with PBS buffer in double foot pads. On the eighth day after immunization, the rats in CD40siRNA group and siRNA group were injected with CD40siRNA expression vector and siRNA expression vector. The rats were sacrificed on day21after inoculation. The histopathologic changes were observed by light microscope and the myocardial histopathology scores were calculated. The expression of RORC mRNA of myocardium was detected by real-time quantitative polymerase chain reaction (RQ-PCR). Enzyme linked immunoabsorption assay (ELISA) was used to determine the serum level of interleukin (IL)-17and interleukin (IL)-23.Results1.Compared with EAM group, the myocardial histopathology score were significantly lower in CD40siRNA group (2.34±0.60vs.3.40±0.35, p<0.05) there is no statistical differences between siRNA group and EAM group (3.56±0.21vs.3.40±0.35, p>0.05)2. Compared with EAM group, the expression of RORC mRNA were significantly lower in CD40siRNA group (2.13±0.28vs.2.93±0.36, p<0.05) there is no statistical differences between siRNA group and EAM group(3.05±0.16vs.2.93±0.36, p>0.05).3. Compared with EAM group, the serum level of IL-17were significantly lower in CD40siRNA group(114.38±8.29vs.148.70±5.04, p<0.05), there is no statistical differences between siRNA group and EAM group(144.15±5.82vs.148.70±5.04,p>0.05).4. Compared with EAM group, the serum level of IL-23were significantly lower in CD40siRNA group (107.00±7.69vs.136.98±23.16, p<0.05), there is no statistical differences between siRNA group and EAM group(142.11±15.87vs.136.98±23.16,p>0.05).Conclusion1. It is suggested that CD40siRNA can reduce myocardial injury.2. It is suggested that CD40siRNA can reduce the expression of RORC mRNA, reduce the serum level of interleukin (IL)-17and interleukin (IL)-23. The mechanism might be that CD40siRNA can interfere the generated of co-stimulating molecules CD40, block CD40-CD40L signaling pathways.