ABSTRACT
Objective To investigate the effect of CD40siRNA on the pathologic changes and T helper lymphocyte (Th)-17 cells of myocardium and IL-17,IL-23 of serum in rats with experimental autoimmune myocarditis (EAM).Methods Forty 6-8 week old healthy male Lewis rats with body weight of 185-210 g were divided into EAM group,CD40siRNA group,siRNA group,and normal control group randomly,with 10 rats in each group.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 8th day after immunization,the rats in CD40siRNA group were injected with CD40 siRNA expression vector,and the rats in siRNA group were injected with siRNA expression vector.The rats were sacrificed on day 21 after 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 (RTPCR).Enzyme linked immunoabsorption assay was used to determine the serum level of IL-17 and IL-23.Results Compared with EAM group,the myocardial histopathology score(2.34 ±0.60 vs 3.40 ±0.35,P ＜0.05),the expression ofRORC mRNA(2.13 ±0.28 vs 2.93 ±0.36,P ＜0.05) and the serum level of IL-17 (114.38 ± 8.29 vs 148.70 ± 5.04,P ＜ 0.05) and IL-23 (107.00 ± 7.69 vs 136.98 ± 23.16,P ＜ 0.05) were significantly lower in CD40 siRNA group.Conclusions It is suggested that CD40 siRNA expression vector might reduce myocardial injury by inhibiting Th-17 activation and down-regulating the expression of IL-17 and IL-23.