Amelioration of coxsackievirus B3-mediated myocarditis by inhibition of tissue inhibitors of matrix metalloproteinase-1

Coxsackievirus B3 (CVB3) is a major cause of acute myocarditis, a serious condition that is refractory to treatment. Myocardial damage results in tissue remodeling that, if too extensive, may contribute to disease. Remodeling is achieved by extracellular proteolysis mediated by the matrix metalloproteinases (MMPs), and MMP activity is counterbalanced by tissue inhibitors of MMPs (TIMPs). We show herein that TIMP-1 expression is induced in the myocardium by CVB3 infection. Surprisingly, TIMP-1 knockout mice exhibited a profound attenuation of myocarditis, with increased survival. The amelioration of disease in TIMP-1 knockout mice was not attributable to either an altered T-cell response to the virus or to reduced viral replication. These data led us to propose a novel function for TIMP-1: its highly localized up-regulation might arrest the MMP-dependent migration of inflammatory cells at sites of infection, thereby anatomically focusing the adaptive immune response. The benefits of TIMP-1 blockade in treating viral myocarditis were confirmed by administering, to wild-type animals, TIMP-1-specific siRNA or polyclonal antisera, both of which diminished CVB3-induced myocarditis. These unexpected findings indicate that increased TIMP-1 expression exacerbates, rather than ameliorates, CVB3-induced myocarditis and, thus, that TIMP-1 may represent a target for the treatment of virus-induced heart disease.     

Progressive interstitial collagen deposition in Coxsackievirus B3-induced murine myocarditis.

Myocardial fibrosis can be produced in certain inbred strains of mice after coxsackievirus B subtype 3 (CVB3) infection. The mechanism responsible for this interstitial matrix alteration is unknown. The presumption is that fibrosis occurs in areas of myocyte damage and inflammation associated with viral infection, analogous to scar formation after cell injury in other organ systems. To test this hypothesis, we examined the hearts of A/J strain mice infected with three CVB3 variants (Crowell [CVB3-CR], Woodruff [CVB3-WD], and Lerner [CVB3-LR]), each known to cause different degrees of acute myocardial injury. With these three variants, virus was present in the heart until day 28 after inoculation but was absent thereafter. Fourteen days after inoculation, inflammation with myocyte necrosis was seen in discrete foci throughout the myocardium with all three variants. Collapse and disorganization of the usually delicate connective tissue matrix identifiable by silver impregnation was seen in these areas of myocyte injury. Persistent, diffuse lymphocytic infiltration of the myocardium was seen 55 days after inoculation with CVB3-WD and CVB3-LR, but hearts initially infected with CVB3-CR showed only rare interstitial lymphocytes comparable to uninfected control hearts. The focal scars produced by myocyte necrosis 14 days after inoculation were accentuated and heavily collagenized 55 days after inoculation with CVB3-WD and CVB3-LR; however, these foci were indistinct 55 days after inoculation with CVB3-CR. Furthermore, the usually delicate network of interstitial collagen fibers surrounding individual myocytes became thickened throughout the heart 55 days after inoculation with CVB3-WD and CVB3-LR, away from visibly scarred areas produced early after infection with these variants. This diffuse reticulin thickening was not seen after infection with the Crowell variant. Only the virus variants associated with persistent interstitial inflammation at day 55 developed major collagen matrix alterations and interstitial fibrosis. We conclude that this persistent interstitial lymphocytic infiltration reflects altered immune function related to specific virus variants in this animal strain. We postulate that these lymphocytes are part of a delayed immunopathogenic response uncoupled from the original viral injury and inflammatory damage. Potential mechanisms by which this interstitial lymphocytic infiltration results in fibrosis are discussed.     

Persistence of virus and viral genome in myocardium after coxsackievirus B3-induced murine myocarditis.

Following infection with Coxsackievirus B3 (CVB3), A-strain mice develop ongoing myocarditis that persists after the virus ceases to be cultivatable from heart tissue. We studied the natural history of this virus-induced but apparently autoimmune inflammation by means of in situ hybridization (ISH) and by polymerase chain reaction (PCR). Both ISH and culture allowed detection of virus up to 2 weeks post-infection in virtually all heart tissues. In contrast, PCR revealed the presence of viral genome for a substantially longer period of time, i.e. at least 34 days after CVB3 infection. Similarly, the majority of mice showed myocardial inflammation at this time point. However, the persistence of virus did not correlate with ongoing myocarditis, and vice versa. Most mice with ongoing myocarditis produced heart myosin autoantibodies, most probably as a result of tissue damage. The lack of correlation between presence of ongoing inflammation and persistence of virus supports our previous view that the late phase of CVB3-induced myocarditis is mediated by autoimmunological mechanisms.     

Coxsackievirus B3-associated myocardial pathology and viral load reduced by recombinant soluble human decay-accelerating factor in mice

Coxsackievirus B3 (CVB3) infection can result in myocarditis, which in turn may lead to a protracted immune response and subsequent dilated cardiomyopathy. Human decay-accelerating factor (DAF), a binding receptor for CVB3, was synthesized as a soluble IgG1-Fc fusion protein (DAF-Fc). In vitro, DAF-Fc was able to inhibit complement activity and block infection by CVB3, although blockade of infection varied widely among strains of CVB3. To determine the effects of DAF-Fc in vivo, 40 adolescent A/J mice were infected with a myopathic strain of CVB3 and given DAF-Fc treatment 3 days before infection, during infection, or 3 days after infection; the mice were compared with virus alone and sham-infected animals. Sections of heart, spleen, kidney, pancreas, and liver were stained with hematoxylin and eosin and submitted to in situ hybridization for both positive-strand and negative-strand viral RNA to determine the extent of myocarditis and viral infection, respectively. Salient histopathologic features, including myocardial lesion area, cell death, calcification and inflammatory cell infiltration, pancreatitis, and hepatitis were scored without knowledge of the experimental groups. DAF-Fc treatment of mice either preceding or concurrent with CVB3 infection resulted in a significant decrease in myocardial lesion area and cell death and a reduction in the presence of viral RNA. All DAF-Fc treatment groups had reduced infectious CVB3 recoverable from the heart after infection. DAF-Fc may be a novel therapeutic agent for active myocarditis and acute dilated cardiomyopathy if given early in the infectious period, although more studies are needed to determine its mechanism and efficacy.     

Suppression of proinflammatory cytokines and induction of IL-10 in human monocytes after coxsackievirus B3 infection

Coxsackievirus B3 (CVB3) causes acute and chronic myocarditis, which is accompanied by an intense mononuclear leukocyte infiltration. Because myocardial tissue damage may either result from viral infections or from a dysregulated immune response, the susceptibility of human monocytes and macrophages to CVB3 was examined in this study with regard to virus replication, virus persistence, and release of cytokines. Monocytes were infected by CVB3 as shown by the intracellular appearance of plus- and minus-strand viral RNA, which was also capable of persisting for more than 10 days. Fresh monocytes were not permissive for full virus replication whereas monocyte-derived macrophages yielded a low amount of new viruses, which led to cell death. Although CVB3 infection induced the mRNA for the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1, and IL-6, only little cytokine production occurred. When infected monocytes were stimulated in addition by lipopolysaccharides (LPS), cytokine production was partially suppressed. In striking contrast, IL-10 expression was strongly and persistently induced by CVB3 on the mRNA and the protein level. These data show a dysregulated cytokine response in CVB3-exposed human monocytes and macrophages, which is characterized by a suppression of proinflammatory cytokines and a dominance of IL-10. This viral strategy may aid CVB3, causing chronic myocardiopathy.     

The viral genetic background determines the outcome of coxsackievirus B3 infection in outbred NMRI mice

The reasons for the different outcome of coxsackievirus B3 (CVB3)-induced heart disease in humans are not well understood. Since there are no experimental data on the course of disease after infection with genetically different CVB3 in a natural variable population until now, we studied the outcome of virus infection in outbred NMRI mice after inoculation of genetically different CVB3 variants. Adult male mice were inoculated with seven closely related CVB3 variants. The histopathological changes of heart and pancreas tissue, antibody induction, virus titers, and persistence of viral positive- as well as negative-strand RNA in spleen and heart tissue were compared at day 7 or day 28 after infection to detect prerequisites and predictive factors for chronic myocarditis. Six CVB3 variants infected NMRI mice. CVB3 infection (i) did not induce detectable myocardial injury, (ii) caused signs of healing up acute myocarditis or (iii) ongoing chronic myocarditis. Neither IgG antibody responses nor the extent of destruction of exocrine pancreatic tissue or viral RNA load in spleen did correlate with myocardial histopathology. In contrast, a high persistent viral RNA load in heart tissue specimens was characteristic for mice developing chronic myocarditis. The results of the present study corroborate high viral load in the acute stage of myocarditis and high amounts of persisting CVB3 RNA in heart tissue as predictive marker of chronic myocarditis. The outcome of CVB3-induced heart disease in outbred NMRI mice depends strongly on the viral genetic background. In particular an important role of viral capsid proteins is suggested.     

IFIH1/MDA5 in the innate immune response to coxsackievirus infection

Genome‐wide association studies identified recently a type 1 diabetes locus in the gene melanoma differentiation‐associated protein‐5 (mda5, also denoted ifih1), coding for the viral RNA sensor MDA5. Variants of mda5 modify the risk for disease development [Smyth et al., 2006 ; Nejentsev et al., 2009 ]. Enteroviruses, such as Coxsackie B viruses (CVB), have been implicated in the aetiology of type 1 diabetes. A recent study was undertaken to determine whether MDA5 is important in the host response to CVB infection [Hühn et al., 2010 ]. C57BL/6 and 129/SvJ mice lacking mda5 were infected with CVB serotype 3 (CVB3). Mice deficient in MDA5 showed a dramatically increased susceptibility to CVB3 infection. The loss of MDA5 allowed the virus to replicate more rapidly, resulting in increased damage of the pancreas and the liver. The pancreatic islet cells were spared from damage, and none of the infected animals developed diabetes or hyperglycemia. It was also found that MDA5 is not absolutely necessary for the induction of type 1 interferons (IFNs), but is required for the production of maximal levels of systemic IFN‐α early after infection. In conclusion, MDA5 plays an important role in the host immune response to CVB3. By restricting virus replication it protects the host from tissue damage and inflammation. These results encourage further studies on the possible role of mda5 in regulating susceptibility to virus‐induced diabetes. J. Med. Virol. 83:1674–1674, 2011. © 2011 Wiley‐Liss, Inc.     

Treatment of coxsackievirus-B3-infected BALB/c mice with the soluble coxsackie adenovirus receptor CAR4/7 aggravates cardiac injury

Coxsackie adenovirus receptor (CAR) is involved in immunological processes, and its soluble isoforms have antiviral effects on coxsackievirus B3 (CVB3) infection in vitro. We explored in this study the impact of CAR4/7, a soluble CAR isoform, on CVB3-induced myocarditis in BALB/c mice. BALB/c mice were treated daily with recombinant CAR4/7, β-galactosidase (β-Gal; as control protein) or buffer for 9 days. Half of each group was infected with CVB3 on day 3, and all mice were killed on day 9. Myocardial CVB3 titer, histology, and serology were analyzed. Treatment with CAR4/7 led to a significant reduction of myocardial CVB3 titer, whereas the application of β-Gal had no detectable effect on the myocardial virus load. CAR4/7 application, however, resulted in increased myocardial inflammation and tissue damage in CVB3-infected hearts, whereas β-Gal caused a degree of cardiac inflammation and injury similar to that in buffer-treated CVB3-infected control animals. CAR4/7 and β-Gal treatment induced the production of antibodies against the respective antigens. CAR4/7-, but not β-Gal-specific, virus-negative sera reacted against myocardial tissue and cellular membranous CAR, and significantly inhibited CVB3 infection in vitro. Thus, CAR4/7 suppressed CVB3 infection in vivo, supporting the concept of receptor analog in antiviral therapy. However, CAR4/7 treatment also leads to an aggravation of myocardial inflammation and injury most likely secondary to an autoimmune process.     

Experimental CVB3-induced chronic myocarditis in two murine strains: Evidence of interrelationships between virus replication and myocardial damage in persistent cardiac infection

In order to analyse the relationships between enteroviral replication and the myocardial damage at the onset of chronic cardiac infection, 2 mouse strains with different degrees of immunological competence (NMRI nu/nu, DBA/2) were infected by a myocarditic Coxsackie virus B3 (CVB3-M1) variant. At 31 days post-inoculation, plaque-forming assay, polymerase chain reaction (RT-PCR), and immunohistochemistry were carried out for detecting viruses and viral components in the myocardium. The virological findings were related to histopathological changes in the myocardium as well to the dilatation of both cardiac ventricles. Chronic myocardial lesions characterized by large fibrosis areas and interstitial inflammatory infiltrates were detected together with cardiomegalia in 52.6% (10/19) of athymic mice and in 9% (2/22) of euthymic mice. Viral replication foci were located and were found only in myocarditic cells adjacent to myocardial inflammatory lesions by immunostaining myocardial tissue sections with anti-serum to VP1 virus capsid protein. Using PCR followed by microwell capture hybridization assay, a large excess of viral positive strand RNA over negative strand was semiquantified in heart tissue from mice with chronic myocarditis, whereas approximately equal amounts of plus and minus strand RNA were detected in cases of persistent cardiac infection without chronic myocardial injuries. These findings provide evidence of the major role of viral replication in the pathogenesis of chronic murine CVB3-induced cardiomyopathy. The results indicate that the cardiac persistence of enteroviral RNAs can be observed without chronic cardiomyopathy, which could be explained by a defective viral positive RNA replication. J. Med. Virol 52:206–214, 1997. © 1997 Wiley-Liss, Inc.     

Galectin-9 administration ameliorates CVB3 induced myocarditis by promoting the proliferation of regulatory T cells and alternatively activated Th2 cells

In this study we explored the effects of galectin-9 on CVB3 induced myocarditis and its possible mechanisms involved. We demonstrated that galectin-9 expression was significantly up-regulated in the myocardium following CVB3 infection and was correlated with the severity of viral myocarditis. To explore whether galectin-9 may have therapeutic effect on the CVB3 induced myocarditis, galectin-9 was administered daily to mice following CVB3 infection. Significantly reduced CD4(+) T cells and remarkably increased regulatory T cells frequency in the heart tissue were found as compared to the non-treated mice. It was accompanied by a significant decreased level of Th1 cytokines as TNF-α and IFN-γ both in the myocardium and serum, and an increased level of Th2 cytokines such as IL-4 and IL-10. Galectin-9 was further found to promote the proliferation of regulatory T cells and elevated IL-4-secreting Th2 cells. It may represent as a novel therapeutic strategy in treating Th1-mediated inflammatory cardiac disease.     

Secondary Heterotypic Versus Homotypic Infection by Coxsackie B Group Viruses: Impact on Early and Late Histopathological Lesions and Virus Genome Prominence

The impact of prior exposure to a different or identical strain of Coxsackievirus B (CVB) on murine CVB myocarditis was studied using a susceptible murine host (A/J[H-2 ^a]) and myocarditic CVB3 or avirulent CVB2 as primary or secondary infectants. The effects of secondary heterotypic infection (CVB2 followed by CVB3) and homotypic infection (CVB3 followed by CVB3) 28 days after primary inoculation, versus CVB2 or CVB3 alone, on injury and viral genomic replication, both early (day 7) and late (days 28 and 56), were evaluated. After the primary infection by CVB2, trivial viral RNA was present in the heart and other organs, and a substantial positivity was observed with CVB3 infection. Seven days after secondary heterotypic (CVB2-CVB3) infection, the quantity of CVB genome in heart, pancreas, liver, and spleen was increased compared with the virus genome in the CVB3-CVB3 group and in the group with primary CVB3 infection alone. This phenomenon was seen in the heart and spleen up to day 28 postsecondary infection. Tissue inflammation and necrosis in heart and pancreas were prominent 7 days postsecondary infection with CVB2-CVB3 and correlated well with an increased quantity of CVB genome. Virus genome was present in heart and spleen 28 days after CVB3 infection alone. Serum CVB3 neutralization titer was increased to 1:128 in CVB2-CVB3 group at days 7 and 28 postsecondary infection, and serum completely neutralized cytopathological effects of CVB3 in the CVB3-CVB3 group at day 7 and 28 postsecondary infection. Our results indicate that secondary heterotypic infection by CVB causes increased injury, inflammation, and CVB replication in target organs such as the heart and pancreas, as well as in immune compartments like the spleen. Compared with CVB3 alone, the intense inflammatory infiltrate in the CVB2-CVB3 group is as not due solely to postviral sensitization of the immune system, but rather to the inability of the host to eradicate the virus.     

Induction of a broad spectrum of inflammation-related genes by Coxsackievirus B3 requires Interleukin-1 signaling

Coxsackievirus B3 (CVB3) is a major cause of acute and chronic forms of myocarditis. Previously, direct viral injury and post-infectious autoimmune response were suspected as main pathogenetic mechanisms. However, induction of pro-inflammatory cytokines may be crucial for pathogenesis in spite of host protein shut off caused by CVB3 replication. We investigated the global expression profile of pro-inflammatory genes induced by acute and persistent (carrier state) CVB3 infection in human fibroblast cell cultures with DNA microarrays, quantitative RT-PCR and ELISA. Rapid induction of a typical spectrum of about 30 inflammation-related genes (e.g., PTGS2, CCL2, IL-1β, IL-6, IL-8, CSF2, MMP-1, MMP-3, and MMP-15) suggested an essential, autocrine role of IL-1. This hypothesis was confirmed by over-expression of IL-1RI, which resulted in a cytokine response upon CVB3 infection in HEK 293 cells otherwise refractory to CVB3-caused gene expression. Blocking IL-1 receptor type I (IL-1RI)-signaling during CVB3 infection with an IL-1 receptor antagonist (IL-1ra) as well as knockdown of IL-1RI using siRNA abrogated cytokine response in human fibroblasts. Both IL-1α and IL-1β are relevant for the induction of inflammation-related genes during CVB3 infection as shown by neutralization experiments. Paracrine effects of IL-1 on the subset of non-infected cells in carrier state infected fibroblast cultures enhanced induction of inflammation-related genes. Conclusions: A broad spectrum of inflammatory cytokines was induced by CVB3 replication via a pathway that requires IL-1 signaling. Our results suggest that IL-1ra may be used as a therapeutic agent to limit inflammation and tissue destruction in myocarditis.     

Secondary enterovirus infection in the murine model of myocarditis. Pathologic and immunologic aspects.

Enteroviruses are implicated as etiologic agents in the inflammatory diseases myocarditis and polymyositis. In this report, we show that a previous enterovirus exposure in mice can influence development of myocardial inflammation with a second enteroviral exposure. Inoculation of 25-day-old male C3H/HeJ mice with 10(3) or 10(5) plaque-forming units (PFU) of infectious or ultra violet (UV)-inactivated coxsackievirus B2 (CVB2), followed by inoculation 28 days later with 10(5) PFU of a myocarditic variant of coxsackievirus B3 (CVB3-m) results in more intense myocardial inflammation and injury than is seen in age-matched mice inoculated with CVB3-m alone. More severe disease occurs with the lower primary dose of CVB2. Neutralizing antibody to CVB2 is detected early after primary inoculation and neutralizing antibody to CVB3 is first detected 5 days after secondary inoculation. In vitro proliferation of splenocytes from mice inoculated with one or both viruses occurs in response to both CVB2 and CVB3 antigens. We recently demonstrated that murine T cells are capable of recognizing an enterovirus group antigen. Thus cell-mediated immune responses to a conserved antigenic epitope(s) among the enteroviruses may be involved in the exacerbation of myocardial inflammatory disease during a second enterovirus infection. The secondary infection model described here may more accurately mirror virus-induced myocarditis in the human population because the majority of adults have been exposed to several enteroviruses before induction of disease.     

RIP3/CaMKⅡ信号通路对重症病毒性心肌炎小鼠心脏功能及生存曲线的影响

目的:观察RIP3/CaMKⅡ信号通路对柯萨奇病毒B3(CVB3)诱导的重症病毒性心肌炎小鼠心脏功能及生存曲线的影响,并探讨CaMKⅡ特异性抑制剂KN-93对心肌损伤的作用。方法:将60只雄性BALB/c小鼠分为正常对照组、CVB3组、CVB3+KN-93组和CVB3+KN-93+Ti(活性氧簇特异性抑制剂)组,以上小鼠腹腔及尾静脉注射药物连续7 d。采用双抗体夹心免疫法检测小鼠心肌细胞坏死标志物,心脏超声技术检测小鼠心脏结构和功能,绘制Kaplan-Meier生存曲线,观察KN-93对小鼠心肌的保护作用。结果:CVB3+KN-93组小鼠心肌细胞坏死较CVB3组显著减轻,心脏功能和生存曲线改善(P<0.01);CVB3+KN-93组小鼠心肌组织H2O2含量较CVB3组显著下降(P<0.01);加入Ti后,CVB3+KN-93+Ti组H2O2含量较CVB3+KN-93组轻度下降(P<0.05),但无论是心脏功能还是生存曲线均无显著差异。结论:RIP3/CaMKⅡ信号通路在CVB3诱导的急性重症病毒性心肌炎小鼠心肌细胞损伤中起到主导作用;KN-93能阻断这种作用并可能产生新的治疗方式,其效果可能是通过对CaMKⅡ的直接抑制和对活性氧簇的间接抑制而实现的。     

Enterovirus infection induces cytokine and chemokine expression in insulin‐producing cells

Despite evidence supporting an association between enterovirus (EV) infection and type 1 diabetes, the etiological mechanism(s) for EV‐induced beta cell destruction is(are) not well understood. In this study, the effects of Coxsackievirus B (CVB) 1–6 on cell lysis and cytokine/chemokine expression in the insulinoma‐1 (INS‐1) beta cell line were investigated. Cytolysis was assessed using tissue culture infectious dose 50 (TCID₅₀). Quantitative RT‐PCR was used to measure viral RNA and mRNA of cytokines interferon (IFN)‐α, IFN‐β, IFN‐γ, tumor necrosis factor (TNF)‐α, and chemokine (C–X–C motif) ligand 10 (CXCL10), chemokine (C–C motif) ligand 2 (CCL2), and chemokine (C–C motif) ligand 5 (CCL5) in infected INS‐1 cells. CVB2, 4, 5, and 6 lysed and replicated in INS‐1 cells; TCID₅₀ was lowest for CVB5 and highest for CVB6. IFN‐γ, CXCL10, and CCL5 mRNA levels all increased significantly following infection with CVB2, 4, 5, and 6 (P < 0.05). CCL2 mRNA increased with CVB2, 5, and 6 (P < 0.05), IFN‐α mRNA increased with CVB5 infection (P < 0.05), while TNF‐α mRNA and IFN‐β mRNA (P < 0.001) increased with CVB2 infection. Dose‐dependent effects of infection on cytokine mRNA levels were observed for all (P < 0.01) except IFN‐γ. Following inoculation of INS‐1 cells with CVB1 and 3, viral RNA was not detected and cytokine/chemokine mRNA levels were unchanged. In conclusion, CVB2, 4, 5, and 6 induce dose‐dependent cytokine and chemokine mRNA production from INS‐1 cells suggesting that pro‐inflammatory cytokine and chemokine secretion by beta cells is a potential mechanism for EV‐induced beta cell damage in type 1 diabetes. J. Med. Virol. 82:1950–1957, 2010. © 2010 Wiley‐Liss, Inc.     

EXPRESSION OF VASCULAR CELL ADHESION MOLECULE-1 IN MURINE HEARTS WITH ACUTE MYOCARDITIS CAUSED BY COXSACKIEVIRUS B3

Cell-mediated autoimmunity has been strongly implicated in the pathogenesis of the myocardial cell damage involved in viral myocarditis. Using a murine model of acute myocarditis caused by Coxsackievirus B3 (CVB3), perforin-expressing killer cells have been shown to infiltrate the heart, and intercellular adhesion molecular-1 (ICAM-1) together with major histocompatibility complex (MHC) antigen was induced on myocardial cells in acute viral myocarditis. To clarify the immunological mechanisms in more detail, the expression of vascular cell adhesion molecular-1 (VCAM-1) has been examined in the heart of acute myocarditis and on cultured cardiac myocytes treated with interferon-gamma (IFN-γ) and tumour necrosis factor-alpha (TNF-α). The effects of in vivo antibody treatment to VCAM-1 on myocardial damage involved in acute myocarditis were also analysed. CVB3-induced myocarditis resulted in enhanced expression of VCAM-1 on myocardial cells. VCAM-1 expression was also induced on cultured cardiac myocytes by treatment with IFN-γ and TNF-α. The in vivo antibody treatment to VCAM-1 decreased the myocardial damage to some extent, but the effects were not statistically significant. These data suggest that the expression of VCAM-1 on myocardial cells may play at least a partial role in the myocardial damage involved in acute viral myocarditis.     

槲皮素对CVB3诱导的新生小鼠病毒性心肌炎氧化应激损伤和炎性反应的调节

目的：心肌炎是由多种不同的感染因子引起的心脏炎症性病变,会造成致命性伤害,尤其是对年轻人。本文旨在探索槲皮素对柯萨奇B3m病毒(CVB3)诱导的新生小鼠病毒性心肌炎氧化应激损伤和炎性反应的影响。方法：CVB3感染建立急性病毒性心肌炎模型。超氧化物歧化酶(SOD)、丙二醛(MDA)和乳酸脱氢酶(LDH)水平通过商业化试剂盒进行检测。ELISA检测IL-1β、IL-6和诱导型一氧化氮合酶(iNOS)水平。蛋白印迹分析TGF-β1、p-NF-κB-P65和TNF-α表达。结果：与正常组相比,CVB3组乳鼠存活率明显降低,心脏重量/体重(HW/BW)比值和血糖浓度明显升高(P<0.05)。槲皮素可抑制CVB3诱导的存活率下降,HW/BW比值和血糖浓度的上升(P<0.05)。与正常组相比,CVB3组SOD水平下降,MDA和LDH水平上升(P<0.05)。槲皮素可减弱CVB3诱导的SOD水平的降低,MDA和LDH水平的升高(P<0.05)。而且,CVB3组乳鼠IL-1β、IL-6和iNOS水平高于正常组(P<0.05)。槲皮素组乳鼠IL-1β、IL-6和iNOS水平低于CVB3组(P<0.05)。与正常组相比,CVB3组TGF-β1、p-NF-κB P65和TNF-α的表达增强(P<0.05)。槲皮素可抑制CVB3诱导的TGF-β1、p-NF-κB P65和TNF-α表达水平的升高(P<0.05)。结论：槲皮素可减轻CVB3诱导的新生小鼠病毒性心肌炎氧化应激损伤和炎症反应。     

汉黄芩苷对柯萨奇B3病毒诱导的病毒性心肌炎小鼠炎症反应的影响

目的:探讨汉黄芩苷对柯萨奇B3病毒(CVB3)诱导的病毒性心肌炎小鼠炎症反应的影响及其可能的调控机制。方法:用CVB3感染BALB/c小鼠构建病毒性心肌炎动物模型。取40只BALB/c小鼠将其随机分为4组:正常对照组、CVB3感染的病毒性心肌炎组、CVB3感染后给予汉黄芩苷处理的治疗组以及CVB3感染后同时给予汉黄芩苷和AKT激动剂处理的激动剂组,每组10只。于药物治疗7 d后处死各组小鼠。用HE染色检测前3组小鼠心肌组织内炎症细胞浸润情况。用ELISA检测前3组小鼠血清中白细胞介素1β(IL-1β)和IL-6含量。用Western blot实验检测前3组小鼠心脏组织中炎症因子蛋白表达水平以及AKT/NF-κB通路的活化情况。最后,通过Western blot实验检测全部4组小鼠心肺组织中AKT/NF-κB通路的活化情况。结果:与正常组相比,病毒性心肌炎小鼠心脏组织内存在大量炎症细胞浸润,而汉黄芩苷治疗显著降低CVB3病毒诱导的心脏组织炎症细胞浸润(P<0.05)。CVB3病毒感染后小鼠血清中IL-1β和IL-6含量较正常组显著升高(P<0.05),而给予汉黄芩苷治疗后小鼠血清中IL-1β和IL-6含量较病毒性心肌炎组显著降低(P<0.05)。Western blot检测结果表明,与病毒性心肌炎组相比,汉黄芩苷治疗显著降低心肌组织内炎症因子(IL-1β和IL-6)蛋白表达水平以及AKT和NF-κB蛋白的磷酸化水平(P<0.05);而给予AKT激动剂处理后,汉黄芩苷对NF-κB蛋白磷酸化水平的抑制作用显著减弱(P<0.05),且汉黄芩苷对炎症因子的下调作用也显著受到抑制(P<0.05)。结论:汉黄芩苷可通过调控AKT/NF-κB通路减轻病毒性心肌炎小鼠的炎症反应。