The in vitro and in vivo antiviral effects of salidroside from Rhodiola rosea L. against coxsackievirus B3

The aim of this study was to investigate the antiviral effects of salidroside, a major component of Rhodiola rosea L. First, the antiviral effects of salidroside against coxsackievirus B3 (CVB3) were determined in vitro and in vivo. Then, the effect of salidroside on the mRNA expression of some important cytokines was measured in hearts of infected BALB/c mice by RT-PCR. Salidroside exhibited obvious antiviral effects both in in vitro and in vivo experiments. Salidroside was found to modulate the mRNA expression of interferon-gamma (IFN-gamma), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-alpha), and interleukin-2 (IL-2). In conclusion, salidroside possesses antiviral activities against CVB3 and it may represent a potential therapeutic agent for viral myocarditis.     

The heart-protective mechanism of nitronyl nitroxide radicals on murine viral myocarditis induced by CVB3

Our previous researches showed that nitronyl nitroxyl derivatives, NNP and NNVP were good anti-oxidants and provided radioprotective effects in C6 cells. The objective of the present study is to investigate the possible antiviral effects and underlying pharmacological of the two nitronyl nitroxide radicals against CVB3 in vitro and in vivo. The results showed that NNP and NNVP were some of the most potent compounds in terms of their antiviral effects by protecting myocardial cells against oxidative damage of free radicals. Treatment with NNP or NNVP could decrease the intracellular ROS level in vitro. They could lead to a significant decrease in activities of biochemical markers AST, CK and LDH in infected murine serum and could increase SOD and CAT activities and decreased MDA activities compared with infected control in vivo. NNP and NNVP could reduce NO production in infected mice by reacting with NO to produce the imino nitroxides which was confirmed by ESR spectrometry. In addition, NNP and NNVP could both decrease the mRNA expression of proinflammatory cytokines, TNF-α, IL-2 and IL-6. In conclusion, nitronyl nitroxide radicals NNP and NNVP were shown to have antiviral activities against CVB3 and they may represent potential therapeutic agents for viral myocarditis.     

柯萨奇病毒B3型诱导的免疫偏离与心肌炎发病关系的研究

目的 研究2种近交系小鼠在柯萨奇病毒B3型(CVB3)感染后辅助性T细胞(Th)免疫偏离对心肌炎发病的影响。方法 用CVB3腹腔感染BALB/c和C57BL/62种近交系小鼠,感染后7d通过检测小鼠血清肌酸激酶(CK)活性,观察心脏外观变化以及心脏石蜡切片H.E染色观察心脏病理改变,比较2种小鼠心肌炎的发病情况;通过体外感染心肌细胞观察病毒复制情况以及体内心脏组织病毒载量的分析,比较2种小鼠对病毒感染和复制的差异;通过检测感染小鼠细胞因子白细胞介素-4(IL-4)、IL-12和γ干扰素(IFN-γ)的表达,抗CVB3VP1抗体的亚型以及T-bet和Gata-3的表达,比较2种小鼠Th免疫偏离的情况。结果 CVB3在体外和体内都可以感染BALB/c和C57BL/6小鼠心肌细胞,但仅BALB/c小鼠感染后可发生明显的病毒性心肌炎,C57BL/6小鼠则不能;BALB/c小鼠感染后表现为Th1型免疫反应而C57BL/6小鼠则偏向于Th2型免疫反应。结论 CVB3感染2种品系小鼠表现为不同的心肌炎发生率,与其诱导了不同类型的免疫偏离密切相关。     

大黄在体内抗柯萨奇病毒B3的实验研究

柯萨奇病毒 (Ｃｏｘｓａｃｋｉｅｖｉｒｕｓ ,ＣＶ)属小核糖核酸病毒科肠道病毒属 ,根据其对乳鼠的致病能力不同分为Ａ、Ｂ两组 ,Ａ组病毒能够引起乳鼠广泛性肌炎及坏死 ,Ｂ组病毒可致局灶性肌炎。研究表明 ,ＣＶＢ是病毒性心肌炎的主要病因[1,2 ] 。为寻找一种有效的抗ＣＶＢ3 治疗药物 ,笔者通过体外实验发现大黄注射液有抗柯萨奇病毒作用[3] ,并根据中药大黄五脏皆治的理论 ,本研究进一步利用ＣＶＢ3 病毒性心肌炎小鼠模型观察了该药的抗病毒作用。现报告如下 :1　材料与方法1.1　细胞Ｈｅｐ 2细胞由武汉大学典型培养物保藏中心提供。细…     

RNA干扰在柯萨奇病毒致心肌炎小鼠模型中的抗病毒研究

为了研究慢病毒介导的shRNA(Short hairpin RNA,shRNA)在柯萨奇B组3型病毒(Coxsackievirus B3,CVB3)导致的心肌炎小鼠模型中的抗病毒作用,合成针对CVB3基因组3753～3771区域的慢病毒Lenti-sh3753,感染HeLa细胞后感染CVB3病毒,通过荧光显微镜观测shRNA的表达和病毒致细胞病变效应,并测定培养上清中的病毒滴度,将慢病毒Lenti-sh3753感染BALB/c小鼠后感染CVB3病毒,观察小鼠的存活率,心脏组织中的病毒滴度和病理变化。结果发现Lenti-sh3753能在HeLa细胞中表达shRNA,并能有效抑制细胞中病毒RNA的复制。在小鼠模型上,Lenti-sh3753能提高小鼠的存活率,降低心脏中的病毒含量,从而减轻病理反应。这些结果提示,Lenti-sh3753在细胞和动物模型中能针对性地降解CVB3病毒RNA,明显降低病毒滴度,有效控制病毒感染。     

H9c2细胞对B组柯萨奇病毒3型重组株的易感性

H9c2细胞是来源于大鼠胚胎心脏组织的成肌细胞系,B组柯萨奇病毒(group B Coxsackievirus,CVB)是心肌炎和扩张型心肌病的主要病原.本研究观察了CVB3在H9c2细胞中的感染性,探讨H9c2细胞是否可用于CVB致心肌疾病的实验研究.用整合了增强型绿色荧光蛋白(EGFP)或海肾荧光素酶(RLuc)的...     

Carvedilol has stronger anti-inflammation and anti-virus effects than metoprolol in murine model with coxsackievirus B3-induced viral myocarditis

Aims

This study aims to compare the effects of carvedilol and metoprolol in alleviating viral myocarditis (VMC) induced by coxsackievirus B3 (CVB3) in mice.

Methods

A total of 116 Balb/c mice were included in this study. Ninety-six mice were inoculated intraperitoneally with CVB3 to induce VMC. The CVB3 inoculated mice were evenly divided into myocarditis group (n = 32), carvedilol group (n = 32) and metoprolol group (n = 32). Twenty mice (control group) were inoculated intraperitoneally with normal saline. Hematoxylin and eosin staining and histopathologic scoring were used to investigate the effects of carvedilol and metoprolol on myocardial histopathologic changes on days 3 and 5. In addition, serum cTn-I levels, cytokine levels and virus titers were determined using chemiluminescence immunoassay, enzyme-linked immunosorbent assay and plaque assay, respectively, on days 3 and 5. Finally, the levels of phosphorylated p38MAPK were studied using immunohistochemical staining and Western blotting on day 5.

Results

Carvedilol had a stronger effect than metoprolol in reducing the pathological scores of VMC induced by CVB3. Both carvedilol and metoprolol reduced the levels of cTn-I, but the effect of carvedilol was stronger. Carvedilol and metoprolol decreased the levels of myocardial pro-inflammatory cytokines and increased the expression of anti-inflammatory cytokine, with the effects of carvedilol being stronger than those of metoprolol. Carvedilol had a stronger effect in reducing myocardial virus concentration compared with metoprolol. Carvedilol was stronger than metoprolol in decreasing the levels of myocardial phosphorylated p38MAPK.

Conclusions

In conclusion, carvedilol was more potent than metoprolol in ameliorating myocardial lesions in VMC, probably due to its stronger modulation of the balance between pro- and anti-inflammatory cytokines by inhibiting the activation of p38MAPK pathway through β1- and β2-adrenoreceptors.     

Coxsackievirus group B type 3 infection upregulates expression of monocyte chemoattractant protein 1 in cardiac myocytes, which leads to enhanced migration of mononuclear cells in viral myocarditis

Coxsackievirus group B type 3 (CVB3) is an important cause of viral myocarditis. The infiltration of mononuclear cells into the myocardial tissue is one of the key events in viral myocarditis. Immediately after CVB3 infects the heart, the expression of chemokine(s) by infected myocardial cells may be the first trigger for inflammatory infiltration and immune response. However, it is unknown whether CVB3 can induce the chemokine expression in cardiac myocytes. Monocyte chemoattractant protein 1 (MCP-1) is a potent chemokine that stimulates the migration of mononuclear cells. The objective of the present study was to investigate the effect of CVB3 infection on MCP-1 expression in murine cardiac myocytes and the role of MCP-1 in migration of mononuclear cells in viral myocarditis. Our results showed that the expression of MCP-1 was significantly increased in cardiac myocytes after wild-type CVB3 infection in a time- and dose-dependent manner, which resulted in enhanced migration of mononuclear cells in mice with viral myocarditis. The migration of mononuclear cells was partially abolished by antibodies specific for MCP-1 in vivo and in vitro. Administration of anti-MCP-1 antibody prevented infiltration of mononuclear cells bearing the MCP-1 receptor CCR2 in mice with viral myocarditis. Infection by UV-irradiated CVB3 induced rapid and transient expression of MCP-1 in cardiac myocytes. In conclusion, our results indicate that CVB3 infection stimulates the expression of MCP-1 in myocardial cells, which subsequently leads to migration of mononuclear cells in viral myocarditis.     

FTY720 alleviates coxsackievirus B3-induced myocarditis and inhibits viral replication through regulating sphingosine 1-phosphate receptors and AKT/caspase-3 pathways

Fingolimod (FTY720) after phosphorylation, as the ligand of sphingosine 1-phosphate receptors (S1PRs), plays an important role in cell proliferation and differentiation. In this article, FTY720 in the treatment of coxsackievirus B3 (CVB3)-induced viral myocarditis was closely related to apoptosis and AKT/caspase-3 apoptotic pathways. We found that CVB3 inhibited myocardial apoptosis at the early stage with upregulating p-AKT level and downregulating activated caspase-3 level for replication of virus progeny, whereas it promoted apoptosis at a late stage with downregulating p-AKT and upregulating activated caspase-3 for releasing the newly synthesized virus to spread. Interestingly, FTY720 could reverse this trend; it promoted apoptosis at an early stage and inhibited apoptosis at the late stage in vivo and vitro, which proved the antiviral effect. We also found that S1PR1, S1PR4, and S1PR5, rather than S1PR2 and S1PR3, were regulated by FTY720 in this process. The results confirmed that FTY720 alleviates CVB3-induced myocarditis and inhibits viral replication through regulating S1PRs and AKT/caspase-3 pathways with a bidirectional regulation of apoptosis.     

Coxsackievirus B3-Induced Chronic Myocarditis in Mouse: Use of Whole Blood Culture to Study the Activation of TNFα-Producing Cells

The pathogenesis of CVB3-induced chronic myocarditis remains unknown. Activated monocytes and macrophages may maintain ongoing inflammation during a persistent CVB3 infection and possibly represent the major mechanism leading to chronic myocarditis. We decided to study the activation status of cells by studying TNFα secretion in vitro using whole blood culture in CVB3-induced murine chronic myocarditis. Seven DBA/2 +/+ mice and 18 NMRI nu/nu mice were inoculated intraperitoneally with 5 × 10⁵ pfu of CVB3, and mice were mock-infected. Thirty-one days post-infection, all mice were sacrificed, blood samples were obtained from the heart, and the heart was removed. Enteroviral genomic detection by RT-PCR, virus isolation and histological analysis of heart samples were performed. Heparinized whole blood (25 μl) was cultured for 4 hr and 24 hr in sterile 96 well-plate containing 225 μl RPMI in the presence or the absence of activators (LPS + PHA). The TNFα levels in the whole blood from mock-infected DBA/2 (n = 4) and NMRI nu/nu mice (n = 5) were not different. A moderate increase of TNFα was observed in three out of five DBA/2 mice with negative CVB3 that had no histological abnormalities in myocardium. An increased level of TNFα was found in the sole DBA/2 mouse with positive CVB3 detection and chronic myocarditis. An increased level of TNFα was found in one out of nine NMRI nu/nu mice with positive CVB3 detection and chronic myocarditis and in one out of seven mice with positive CVB3 detection exempt of lesions in myocardium. In other infected mice, the level of TNFα was normal. Enteroviral genome was not detected in the blood from infected mice at 31 days post-infection. The increased TNFα level in some mice may be designed for a beneficial inflammatory and immune response, however, an exaggerated release may be associated with an adverse effect. The normal TNFα level in whole blood cultures from mice with chronic myocarditis does not exclude enhanced cytokine production at infected loci such as myocardial tissue. This is the first report to use whole blood cultures to study the production of cytokines in virus-induced disease in a small animal model.     

Low‐intensity pulsed ultrasound attenuates cardiac inflammation of CVB3‐induced viral myocarditis via regulation of caveolin‐1 and MAPK pathways

The aggressive immunological activity elicited by acute viral myocarditis contributes to a large amount of cardiomyocytes loss and poor prognosis of patients in clinic. Low‐intensity pulsed ultrasound (LIPUS), which is an effective treatment modality for osteoarthropathy, has been recently illustrated regulating the overactive inflammatory response in various diseases. Here, we aimed to investigate whether LIPUS could attenuate coxsackievirus B3 (CVB3) infection‐induced injury by coordinating the inflammatory response. Male BALB/c mice were inoculated intraperitoneally with CVB3 to establish the model of acute viral myocarditis. LIPUS treatment was given on Day 1, Day 1, 3 and Day 1, 3, 5 post‐inoculation, respectively. All mice were followed up for 14 days. Day 1, 3, 5 LIPUS treatment significantly improved the survival rate, attenuated the ventricular dysfunction and ameliorated the cardiac histopathological injury of CVB3‐infected mice. Western blotting analysis showed Day 1, 3, 5 LIPUS treatment decreased pro‐inflammatory cytokines, increased the activation of caveolin‐1 and suppressed p38 mitogen‐activated protein kinase (MAPK) and extracellular signal‐regulated kinase (ERK) signallings in heart tissue. RAW264.7 cells were treated with lipopolysaccharides (LPS) to simulate the augmented inflammatory response in vivo. LIPUS treatment on RAW264.7 inhibited the expression of pro‐inflammatory cytokines, activated caveolin‐1 and suppressed p38 MAPK and ERK signallings. Transfecting RAW264.7 with caveolin‐1 siRNA blunted the suppression of pro‐inflammatory cytokines and MAPK signallings by LIPUS treatment. Taken together, we demonstrated for the first time that LIPUS treatment attenuated the aggressive inflammatory response during acute viral myocarditis. The underlying mechanism may be activating caveolin‐1 and suppressing MAPK signallings.     

Antiviral Effect of Interferon-Induced Guanylate Binding Protein-1 against Coxsackie Virus and Hepatitis B Virus B3 in Vitro

Guanylate binding protein-1(GBP-1)is an interferon-induced protein.To observe its antiviral effect against Hepatitis B virus(HBV)and Coxsackie virus B3(CVB3),we constructed an eukaryotic expression vector of human GBP-1(hGBP-1).Full-length encoding sequence of hGBP-1 was amplified by long chain RT-PCR and inserted into a pCR2.1 vector,then subcloned into a pCDNA3.1(-)vector.Recombinant hGBP-1 plasmids and pHBV1.3 carrying 1.3-fold genome of HBV were contransfected into HepG2 cells,and inhibition effect of hGBP-1 against HBV replication was observed.Hela cells transfected with recombinant hGBP-1 plasmids were challenged with CVB3,and viral yield in cultures were detected.The results indicated that recombinant eukaryotic expression plasmid of hGBP-1 was constructed successfully and the hGBP-1 gene carried in this plasmid could be efficiently expressed in HepG2 cells and Hela cells.hGBP-1 inhibit CVB3 but not HBV replication in vitro.These results demonstrate that hGBP-1 mediates an antiviral effect against CVB3 but not HBV and perhaps plays an important role in the interferon-mediated antiviral response against CVB3.     

Antiviral Effect of Interferon-Induced Guanylate Binding Protein-1 against Coxsackie Virus and Hepatitis B Virus B3 in Vitro

Guanylate binding protein-1(GBP-1) is an interferon-induced protein. To observe its antiviral effect against Hepatitis B virus (HBV) and Coxsackie virus B3 (CVB3), we constructed an eukaryotic expression vector of human GBP-1(hGBP-1). Full-length encoding sequence of hGBP-1 was amplified by long chain RT-PCR and inserted into a pCR2.1 vector, then subcloned into a pCDNA3.1(-) vector. Recombinant hGBP-1 plasmids and pHBV1.3 carrying 1.3-fold genome of HBV were contransfected into HepG2 cells, and inhibition effect of hGBP-1 against HBV replication was observed. Hela cells transfected with recombinant hGBP-1 plasmids were challenged with CVB3, and viral yield in cultures were detected. The results indicated that recombinant eukaryotic expression plasmid of hGBP-1 was constructed successfully and the hGBP-1 gene carried in this plasmid could be efficiently expressed in HepG2 cells and Hela cells. hGBP-1 inhibit CVB3 but not HBV replication in vitro. These results demonstrate that hGBP-1 mediates an antiviral effect against CVB3 but not HBV and perhaps plays an important role in the interferon-mediated antiviral response against CVB3.     

Truncated monocyte chemoattractant protein‐1 can alleviate cardiac injury in mice with viral myocarditis via infiltration of mononuclear cells

BALB/c mice inoculated intraperitoneally with coxsackievirus group B type 3 (CVB3) were allocated to five groups; namely, a viral myocarditis group infected with CVB3 alone (control group), an antibody intervention group that received intracardiac anti‐MCP‐1, an antibody intervention control group that received goat IgG, a tMCP‐1 intervention group that received plasmid pVMt expressing tMCP‐1, and a tMCP‐1 intervention control group that received plasmid pVAX1. There was also a normal control group. The ratio of murine heart weight to body weight, pathological score of myocardial tissue, serum creatine kinase‐MB titers and CVB3 loading of myocardial tissue were assessed. The cardiac lesions in mice that received 20, 40 or 60 µg pVMt (P < 0.05) were less severe than those in control mice with untreated viral myocarditis. In addition, fewer mononuclear cells had infiltrated the myocardium of mice who received 40 or 60 µg pVMt intramyocardially (P < 0.01), whereas there was no difference in mononuclear cell infiltration between mice with viral myocarditis and those that received 20 µg pVMt (P > 0.05). There was also no difference between mice that received anti‐MCP‐1 antibody and those that received 40 µg pVMt in ratio of HW/BW, serum CK‐MB titers and pathological score (P > 0.05). This study showed that tMCP‐1 can alleviate cardiac lesions and cardiac injury in mice with viral myocarditis via infiltration of mononuclear cells. Thus, tMCP‐1 may be an alternative to anti‐MCP‐1 antibody treatment of viral myocarditis. Further research is required.     

Antiviral effect of interferon-induced guanylate binding protein-1 against Coxsackie virus and Hepatitis B virus B3 <Emphasis Type="Italic">in Vitro</Emphasis>

Guanylate binding protein-1(GBP-1) is an interferon-induced protein. To observe its antiviral effect against Hepatitis B virus (HBV) and Coxsackie virus B3 (CVB3), we constructed an eukaryotic expression vector of human GBP-1(hGBP-1). Full-length encoding sequence of hGBP-1 was amplified by long chain RT-PCR and inserted into a pCR2.1 vector, then subcloned into a pCDNA3.1(−) vector. Recombinant hGBP-1 plasmids and pHBV1.3 carrying 1.3-fold genome of HBV were contransfected into HepG2 cells, and inhibition effect of hGBP-1 against HBV replication was observed. Hela cells transfected with recombinant hGBP-1 plasmids were challenged with CVB3, and viral yield in cultures were detected. The results indicated that recombinant eukaryotic expression plasmid of hGBP-1 was constructed successfully and the hGBP-1 gene carried in this plasmid could be efficiently expressed in HepG2 cells and Hela cells. hGBP-1 inhibit CVB3 but not HBV replication in vitro. These results demonstrate that hGBP-1 mediates an antiviral effect against CVB3 but not HBV and perhaps plays an important role in the interferon-mediated antiviral response against CVB3. Foundation item: National Natural Science Foundation (No.30271170, No.30170889).     

桂皮醛对小鼠柯萨奇病毒诱发病毒性心肌炎的作用(英文)

已知Toll样受体4(Toll-like receptors 4,TLR4)及其下游信号组分在柯萨奇病毒(CoxsackievirusB,CVB)诱发的病毒性心肌炎中扮演重要的角色,其在治疗中的作用仍不明确。桂皮醛具有抗病毒以及成剂量依赖性抑制由TLR4诱导的核因子活性的作用,而其对病毒性心肌炎的作用机制尚不明确。我们的实验结果显示:在体外,桂皮醛对正常心肌细胞的IC50为15μM;100-1000μM桂皮醛能显著抑制心肌细胞中的病毒滴度(P0.01),而细胞存活率与CVB组无统计学差异(P0.01)。而在病毒性心肌炎小鼠体内,与模型组比较,20和40mg/kg桂皮醛i.p.使第7 d血清中NO的含量以及心肌中诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS),肿瘤坏死因子(tumor necrosis factor,TNF-α),核因子κB P65(nuclear factor-κB P65,NF-κB P65)和TLR4蛋白质表达显著降低(P0.05)。降低第21 d心脏体重比(Heat Weight/Body Weight,Hw/Bw)比值,提高小鼠生存率,减轻病理损伤的作用。这些结果显示桂皮醛虽在体外无抗病毒活性,但其在体内具有降低病毒滴度和抑制TLR-4-NF-κB信号传导的作用,对病毒性心肌炎小鼠具有治疗作用。桂皮醛可能通过对TLR-4-NF-κB信号传导抑制作用,作为一种新的方法治疗病毒性心肌炎。     

大黄在体内抗柯萨奇病毒B3的实验研究

In order to search a effective therapy for viral myocarditis, anti vial activity of Rheum officinale on Coxsackieivirus B3 (CVB3) was evalu ated in BALB/C mice. After being determined optium scheme with orthogonal design , mice infected with CVB3 were treated with Rheum officinale, ribavirin an d 0.9% NaCl. The survival rates of the mice were 35%,5% and 5%;Median survival time were 23,11 and 10.5 days;Infectious viral titers were 10-3.2 ,10-4.7 and 10-4.7 TCID50/0.1 mL repectively, The lesion s of cardiac tissues lightened in mice treated with Rheum offinicale. These results showed that Rheum officinale was effective in treatment of CVB3 in fected mice. The study provided scientific basis for further research and widen antiviral spectrum of Rheum officinale.     

免疫系统在病毒性心肌炎发病中的作用

心肌炎通常由病毒感染引起,有证据表明心肌炎最终发展成扩张性心肌病,是发达国家主要致死的原因,越来越多的人认为细胞因子在心肌炎和心肌病发病中起重要作用,心力衰竭病人血循环中细胞因子水平较正常人高。已证明多种细胞因子能在体内外抑制心肌收缩,细胞因子由活化的免疫细胞产生,它可诱生NO合酶,继而产生NO,已证明NO既有利又有害,关键在于产生NO量的多少,NO能抑制病毒复制,而保护心脏抗柯萨奇B病毒感染,无论是病毒感染对心脏的直接作用,还是免疫应答的利弊平衡,对此两者分子机制的了解都将是掌握人类心肌炎发病的关键。     

TNFR-Fc fusion protein expressed by in vivo electroporation improves survival rates and myocardial injury in coxsackievirus induced murine myocarditis

Tumor necrosis factor-alpha (TNF-alpha) is one of the major cytokines that modulate the immune response in viral myocarditis, but its role has not yet been thoroughly evaluated. We antagonized TNF-alpha using the expressed soluble p75 TNF receptor linked to the Fc portion of the human IgG1 gene (sTNFR:Fc) by in vivo electroporation, and evaluated its effects on experimental coxsackieviral B3 (CVB3) myocarditis. A plasmid DNA encoding sTNFR:Fc (15microg/mouse) was injected into the gastrocnemius muscles of Balb/C male mice followed by electroporation (day -1). Control mice were injected with an empty vector. One day after electroporation, mice were infected with CVB3 (day 0). Serum levels of sTNFR:Fc increased from day 2 and peaked at day 5 following electroporation. The heart virus titers of sTNFR:Fc mice were higher than those of controls at day 3. However, subsequent to day 12, the survival rates of the sTNFR:Fc mice were significantly higher than those of the controls (36% versus 0% at day 27, P<0.01). Histopathological examination indicated that inflammation and myocardial fibrosis were significantly decreased in sTNFR:Fc mice at day 12. The expressed sTNFR:Fc could modulate the inflammatory process during the post-viremic phase of viral myocarditis.     

Antiviral and myocyte protective effects of murine interferon-beta and -{alpha}2 in coxsackievirus B3-induced myocarditis and epicarditis in Balb/c mice

The present study tested the hypothesis that murine (m)IFN-beta or mIFN-alpha(2) can eliminate cardiac viral load and protect cardiomyocytes from injury in animals infected with coxsackievirus B3 (CVB3). CVB3-inoculated male Balb/c mice exhibited signs of illness, including lethargy, progressive weight loss, and death (10% on day 3 and 100% on day 8). Cardiac viral load was high [4,277 +/- 1,009 plaque-forming units and 25 +/- 5 copies CVB3/hypoxanthine guanine phosphoribosyl transferase 1 mRNA] on day 4. The cardiac tissue exhibited severe inflammatory infiltration and myocyte damage with an average myocarditis integrated pathology score of 2.1 +/- 0.2 on day 7. Most of the mice infected with CVB3 also developed epicarditis, and 55% had intraventricular thrombi present. Treatment with mIFN-beta [2.5 to 10 million international units (MIU)/kg] dose-dependently improved the general health status in CVB3-inoculated mice, as evidenced by reduction in weight loss, prevention of death, elimination of cardiac viral load, protection of myocytes from injury, decrease in inflammatory cell infiltration, and attenuation of intraventricular thrombus formation. Treatment with 10 MIU/kg mIFN-alpha(2) resulted in a similar level of efficacy as that induced by 5 MIU/kg mIFN-beta, with the exception that mIFN-alpha(2) did not reduce cardiac CVB3 mRNA. However, mIFN-alpha(2) , but not any dose group of mIFN-beta, significantly attenuated CVB3-induced epicarditis. These data demonstrate antiviral effects for both mIFN-beta and mIFN-alpha(2), which lead to protection of the mice from CVB3-induced myocarditis. However, the potential mechanisms leading to a differential host response for the two isoforms of mIFN remain to be elucidated.