炙甘草汤对实验性自身免疫性心肌炎的治疗作用及机制研究

Therapeutic effects and mechanisms of Zhigancao Decoction on experimental autoimmune myocarditis

目的探讨炙甘草汤对实验性自身免疫性心肌炎的疗效及可能的作用机制。方法40只BALB/c鼠随机分成空白对照组、实验性自身免疫性心肌炎(EAM)组、炙甘草汤组及强的松组各10只。采用重组α肌球蛋白重链多肽(MyHC-α)诱导小鼠制备实验性自身免疫性心肌炎(EAM)模型。将弗氏佐剂与MyHC-α等体积混合,分别在第0 d和第7 d双足底注射于EAM组、炙甘草汤组和强的松组的小鼠,空白对照组注射等体积的弗氏佐剂。从第8 d起通过灌胃的方式给予炙甘草汤组小鼠炙甘草汤(22.76 g/kg,1/d),强的松组小鼠给予强的松(7.6 mg/kg,1/d),空白对照组和EAM组小鼠给予等体积生理盐水。持续给药14 d后利用HE染色观察各组小鼠心肌组织的病理性改变。流式液相多重蛋白定量技术检测心肌组织匀浆液中细胞因子干扰素γ(IFN-γ)、白介素4(IL-4)、白介素17A(IL-17A)、白介素10(IL-10)、白介素1α(IL-1α)、白介素6(IL-6)、肿瘤坏死因子-α(TNF-α)水平;流式细胞术检测各组脾脏CD4+T细胞亚群分布。结果EAM组的小鼠在免疫后心肌组织切片HE染色表现为典型的心肌炎改变,心内膜表面变色和广泛的心肌炎症细胞浸润。EAM组中小鼠心肌组织匀浆细胞因子IFN-γ、IL-1α、IL-6水平均较空白对照组有显著升高,差异有统计学意义(P<0.05);脾脏中辅助性T细胞1(Th1)、辅助性T细胞17(Th17)水平在免疫后较空白对照组也有显著升高(P<0.05),但辅助性T细胞2(Th2)水平变化不明显。炙甘草汤组能显著减轻心肌组织的炎症反应,心脏中细胞因子IFN-γ、IL-6、IL-1α水平较EAM组均显著降低(P<0.05),脾脏中Th1、Th17细胞水平较EAM组也显著下降(P<0.05)。结论炙甘草汤在EAM发展中能够减轻炎症反应,通过减少活化的炎症细胞及抑制心肌中的炎症细胞因子分泌来对抗EAM,改善心肌炎症反应,降低心肌损伤。

Objective To explore the therapeutic effects and possible mechanisms of Zhigancao Decoction on experimental autoimmune myocarditis.Methods Forty BALB/c mice were randomly divided into a blank control group,experimental autoimmune myocarditis(EAM)group,a Zhigancao Decoction group,and a prednisone group(n=10 each).The experimental autoimmune myocarditis(EAM)model was created by inducing mice with recombinant alpha myosin heavy chain polypeptide(MyHC alpha).Freund's adjuvant was mixed with an equal volume of MyHC-αand was intraplantar injected into the EAM group,Zhigancao Decoction group and prednisone group on days 0 and 7,respectively,and the blank control group was injected with an equal volume of Freund's adjuvant.From day 8,the Zhigancao Decoction group was treated with Zhigancao Decoction(22.76 g/kg,1/d),the prednisone group was administered prednisone(7.6 mg/kg,1/d),whereas mice in the blank control group and the EAM group received an equal volume of saline.HE staining was utilized to observe the pathological changes in the myocardial tissues of mice in each group after continued administration for 14 days.Levels of cytokines interferon-gamma(IFN-γ),interleukin 4(IL-4),interleukin 17a(IL-17A),interleukin 10(IL-10),interleukin 1 alpha(IL-1α),interleukin 6(IL-6),and tumour necrosis factor-alpha(TNF-α)were measured in myocardial tissue homogenates by flow cytometric multiplex protein quantification.The distribution of CD4+T cell subsets in the spleen of each group was detected by flow cytometry.Results Mice in the EAM group exhibited typical myocarditis changes,endocardial surface discolouration and extensive myocardial inflammatory cell infiltration by HE staining of myocardial tissue sections after immunization.The levels of cytokines IFN-γ,IL-1α,and IL-6 in myocardial homogenates of mice in the EAM group were all significantly increased compared with those in the blank control group (P<0.05). The levels of helper 1 (Th1) and helper 17 (Th17) cells in the spleen were also significantly increased compared with the blank control after immunization (P<0.05), but the levels of helper 2 (Th2) cells did not change significantly. Zhigancao Decoction group significantly attenuated the inflammatory response in myocardial tissue, the levels of cytokines IFN-γ, IL-6, and IL-1α in the heart were all significantly decreased compared with the EAM group (P<0.05), and the levels of Th1 and Th17 cells in the spleen were also significantly decreased compared with the EAM group (P<0.05). Conclusion Zhigancao Decoction in the development of EAM is able to attenuate inflammatory responses and combat EAM by reducing activated inflammatory cells as well as inhibiting inflammatory cytokine secretion in the myocardium, thereby improving myocardial inflammatory responses and reducing myocardial injury.