Excess amount of cytokine produced by inflammatory stimuli contributes to the progression of myocardial damage in myocarditis. Some angiotensin II receptor type 1 antagonists are reported to inhibit proinflammatory cytokine production in vitro and in vivo. We tested the hypothesis that olmesartan, a novel angiotensin II receptor type 1 antagonist, ameliorated experimental autoimmune myocarditis (EAM) in rats attributing to the suppression of inflammatory cytokines in the heart. We orally administered olmesartan 1, 3, and 10mg/kg/day to rats with EAM for 3 weeks. The results showed that olmesartan decreased blood pressure significantly compared with the untreated group, but markedly reduced the severity of myocarditis by comparing the heart weight/body weight ratio, pericardial effusion scores, macroscopic scores and microscopic scores. Myocardial interleukin (IL)-1β expression by western blotting and IL-1β-positive staining cells by immunohistochemistry were significantly lower in rats with EAM given olmesartan treatment compared with those of rats given vehicle. We conclude that Olmesartan ameliorates acute EAM in rats. The cardioprotection of olmesartan may be due to suppression of inflammatory cytokines dependent of the hemodynamic modifications.

Objective: Recent evidence has suggested that peroxisome proliferator-activated receptor-(PPAR- ) serves as a negative regulator in the immune system. In the present study, we investigated the expression of PPAR-and the effect of PPAR-ligands on experimental autoimmune myocarditis (EAM).Methods and Results: Experimental autoimmune myocarditis was induced in Lewis rats by immunization with porcine cardiac myosin. PPAR-γ ligands 15-deoxy- 12,14-PGJ2 200μg·kg−1·d−1 by ip and pioglitazone 10mg·kg−1·d−1 by oral were administered for 3 weeks. PPAR-γexpression was upregulated in myocarditis and the enhanced PPAR-γ expression was prominently stained in the nuclear and perinuclear regions of the positive-stained cells in the inflammatory lesions. Administration of PPAR-γ ligands markedly reduced the severity of myocarditis, as indicated by the heart weight/body weight ratio, pericardial effusion scores, macroscopic scores, and microscopic scores. The upregulated PPAR- expression was also reduced by PPAR-γ ligands treatment. In addition, PPAR-ligands suppressed the proliferative response and interferon-production of T cell-enriched splenocytes from rats with EAM. Furthermore, the cytotoxic activity and myocarditogenic potential of these T cells were inhibited by PPAR-γ ligands treatment. Conclusions: PPAR-γ ligands ameliorate EAM associated with inhibition of expansion and activation of the self-sensitive T cells. These results suggest that PPAR-ligands may have the potential to modulate human inflammatory heart diseases as myocarditis.

目的探讨过氧化物酶体增殖因子活化受体（PPARγ）在急性心肌炎发病中的作用；PPARγ配体治疗对急性心肌炎的影响及其可能的作用机制。方法6周龄Lewis大鼠注射猪心肌球蛋白诱导自身免疫性心肌炎（EAM）大鼠36只。分为正常对照、阳性对照、15d2PGJ2治疗组及比格列酮治疗组，每组9只。22天后大鼠麻醉状态下开胸，用免疫组化法观察PPARγ在炎症心肌中的表达及PPARγ配体15d2PGJ2注射（200μg·kg- 1·d - 1）和比格列酮口服（10mg·kg- 1·d-1）治疗对心肌炎症程度，及对致敏T细胞的增殖、活化和致心肌炎能力的影响。结果PPARγ在炎症心肌组织中表达增强，主要定位在炎性浸润细胞的核和核周围区；15d2PGJ2和比格列酮治疗使心肌炎症得到减轻，心重P体重、炎症分级严重程度明显减轻；免疫组化分析招募入炎性病灶内的CD4+、CD8+细胞和巨噬细胞数目，15d2PGJ2和比格列酮治疗明显减少病灶内炎性细胞浸润：与阳性对照组相比，病灶内巨噬细胞（22±4、26±6 vs 45±8，分别P<0101）、CD4+ 细胞（8±2、10±3 vs 18±5，P<0101）和CD8+细胞（3±1、4±2 vs 7±2，分别P<0101和<0105） 数目明显减少。体外实验证实PPARγ配体抑制富含T细胞的脾和淋巴结细胞增殖反应及γ干扰素产生；致敏T淋巴结细胞对其特异的抗原（心肌细胞）的细胞毒分析表明，免疫诱导后给予15d2PGJ2治疗组和比格列酮治疗组与阳性对照组相比其淋巴结细胞的细胞毒活性被显著抑制。心肌炎大鼠致敏T淋巴细胞过继转染注射后，受体鼠均被诱发心肌炎，PPARγ配体治疗抑制EAM大鼠致敏T细胞的致心肌炎能力。结论PPARγ配体治疗减轻实验性自身免疫性心肌炎，其机制与抑制T细胞增殖反应及活化和抑制自身反应性T细胞的致心肌毒作用有关。

Objective: To test the hypothesis that activation of peroxisome proliferator activated receptor c (PPAR-c) reduces experimental autoimmune myocarditis (EAM) associated with inhibitor kB (IkB) a induction, blockade of nuclear factor kB (NF-kB), and inhibition of inflammatory cytokine expression. Methods: EAM was induced in Lewis rats by immunisation with porcine cardiac myosin. PPAR-c activators 15-deoxy-D12, 14-prostaglandin J2 (15d-PGJ2) and pioglitazone (PIO) were administrated to rats with EAM. Results: Enhanced PPAR-c expression was prominently stained in the nuclear and perinuclear regions of infiltrating inflammatory cells. Administration of 15d-PGJ2 and PIO greatly reduced the severity of myocarditis and suppressed myocardial mRNA and protein expression of inflammatory cytokines in rats with EAM. In addition, treatment with PPAR-c activators enhanced IkB concentrations in the cytoplasmic fractions and nuclear fractions from inflammatory myocardium. Concurrently, NF-kB was greatly activated in myocarditis; this activation was blocked in the 15d-PGJ2 treated and PIO treated groups. Conclusions: PPAR-cmay have a role in the pathophysiology of EAM. Because an increase in IkB expression and inhibition of translocation of the NF-kB subunit p65 to the nucleus in inflammatory cells correlated with the protective effects of PPAR-c activators, these results suggest that PPAR-c activators act sequentially through PPAR-c activation, IkB induction, blockade of NF-kB activation, and inhibition of inflammatory cytokine expression. These results suggest that PPAR-c activators such as 15d-PGJ2 and PIO may have the potential to modulate human inflammatory heart diseases such as myocarditis.

We investigated whether carvedilol protects against experimental autoimmune myocarditis (EAM) attributing to antioxidant properties. Acute EAM was induced by porcine cardiac myosin in Lewis rats. We orally administered a vehicle, various dosages of carvedilol, metoprolol, or propranolol to rats with EAM for 3 weeks. Three β-blockers decreased heart rates to the same extent. Carvedilol, but not metoprolol or propranolol, markedly reduced the severity of myocarditis at the two different dosages. Only carvedilol decreased the myocardial protein carbonyl contents, and also decreased the myocardial thiobarbituric acid reactive substance products in rats with EAM. Accordingly, carvedilol protects against acute EAM in rats, and this superior cardioprotective effect of carvedilol to metoprolol and propranolol may be due to the antioxidant properties in addition to the hemodynamic modifications.

Thioredoxin (TRX) is a redox regulatory protein that protects cells from various stresses. Angiotensin-converting enzyme (ACE) inhibitor was reported to enhance endogenous antioxidant enzyme activities. This study was carried out to investigate whether temocapril, a novel non-sulfhydryl containing ACE inhibitor, reduces the severity of myocarditis via redox regulation mechanisms involving TRX. Western blot showed that temocapril enhanced cytosolic redox regulatory protein TRX expression, but neither mitochondrial TRX2 nor antioxidant enzymes, such as copper-zinc superoxide dismutase (Cu/Zn-SOD) or manganese superoxide dismutase (Mn-SOD) expression, was increased by the preconditioning treatment. In rats with experimental autoimmune myocarditis (EAM), the protein carbonyl content, a marker of cellular protein oxidation, was increased accompanied with enhanced TRX expression. An immunohistochemical study showed that TRX stain was enhanced in infiltrating inflammatory cells and in damaged myocytes. The severity of the myocarditis and the protein carbonyl contents were less increased in temocapril treatment (10mg/kg/day, orally) from day 1 to day 21 in which TRX was up regulated when the inflammation started, but not in temocapril treatment from day 15-21 in which TRX was not up-regulated when the inflammation started. The results suggest that TRX and the redox state modified by TRX may play a crucial role in the pathophysiology of EAM. Temocapril ameliorates myocarditis associated with inducing TRX increase in a preconditioning manner, although the mechanism of TRX induction by temocapril remains to be elucidated.

Excessive production of nitric oxide (NO) by inducible NO synthase (iNOS) contributes to the progression of myocardial damage in myocarditis. Some dihydropyridine calcium channel blockers reportedly inhibit NO production and proinflammatory cytokines and the present study sought to clarify if a low dose of benidipine, a novel dihydropyridine calcium channel blocker, would ameliorate experimental autoimmune myocarditis (EAM). Rats with or without myocarditis were administered oral benidipine at a dose of 3mg·kg-1·day-1 for 3 weeks. Low-dose benidipine did not decrease blood pressure significantly compared with the untreated group, but markedly reduced the severity of myocarditis. Myocardial interleukin-1β(IL-1β) expression and IL-1β-positive cells were significantly less in rats with EAM that were treated with low-dose benidipine compared with untreated ats. Also, myocardial iNOS expression and iNOS-positive cells were markedly reduced in in the treated rats compared with the untreated group. Furthermore, myocardial NO production and nitrotyrosine expression were suppressed by the treatment in rats with EAM. The cardioprotection of low-dose benidipine may be caused by suppression of inflammatory cytokines and inhibition of NO production.

Peroxisome proliferator-activated receptors (PPARs) are members of a nuclear hormone receptor superfamily of ligand-activated transcriptional factors1 Recent data have shown that the prostaglandin ( PG), 152deoxy2-12,142PGJ2 (15d2PGJ2), and synthetic antidiabetic thiazolidinedione (TZDs), which are PPAR2γligands, suppress T cell proliferative response in vitro and inhibit inflammatory cytokine production by cells of monocyte/macrophage lineage11 Importantly, PPAR2γ ligands have been shown to ameliorate a variety of inflammatory conditions, including atherosclerosis, arthritis, inflammatory bowel disease and experimental autoimmune encephalomyelitis1-To explore the role of PPAR2γligands during the pathogenesis of experimental autoimmune myocarditis (EAM), we examined myocardial PPAR2γexpression in rats with EAM1 We also examined the effect of PPAR2γligands 15d2PGJ2 and plioglitazone on myocardial inflammation and on the expression of inflammatory cytokines1

目的特莫普利是否能通过加强氧化还原调节机制减轻心肌炎。方法Lewis大鼠自身免疫性心肌炎及离体培养的心肌细胞，免疫杂交检测特莫普利治疗前后硫氧化还原蛋白（TRX）表达，及其对心肌炎的影响。结果特莫普利加强心肌细胞胞质定位的TRX表达，但对线粒体定位的TRX2表达则无明显改变。超氧化物歧化酶表达也无明显变化。特莫普利治疗从第1～21天，可减轻心肌炎的严重程度和降低氧化蛋白含量；但治疗从第15～21天，则无明显效果。本组心肌炎模型炎症大致从第15天开始，到21d达高峰，特莫普利从第1～21天治疗，可看做有2周的预治疗来上调心肌细胞TRX表达，通过加强TRX表达减轻心肌炎症。结论TRX和经TRX修饰的氧化还原状态在自身免疫性心肌炎的发病中起重要作用，特莫普利治疗通过加强心肌TRX表达减轻心肌炎症

目的探讨过氧化物酶体增殖因子活化受体γ（PPAR）在急性心肌炎发病中的作用；PPARγ配体治疗能否减轻心肌炎及其可能的机制。方法6周龄雄性Lewi8大鼠24只诱导自身免疫性心肌炎，随机分为阳性对照、15d-PGJ：治疗组及比格列酮治疗组（各组8只），正常大鼠8只作为正常对照。观察PPARγ配体15 d-PGJ：注射（200Mg•kg～d-'）和比格列酮口服（10mg.d'）治疗对心肌炎症程度的影响；免疫组化检测心肌PPAR'y表达、免疫杂交检测IKBd、IL。113和TNFa蛋白表达；核酸酶保护法检测心肌组织促炎细胞因子mRNA表达、电泳迁移率变动分析检测NF’KB的DNA结合活性。结果①PPARγ在炎症心肌组织中表达增强，主要定位在炎性浸润细胞的核和核周围区；②15d-PGJ：和比格列酮治疗使心肌炎症得到减轻，心重/体重、炎症分级严重程度明显减轻；③PPARγ配体15d-PGJ：和比格列酮治疗明显降低心肌组织中多种炎性细胞因子Mrna表达，及降低心肌内上调的IL-1p和TNFa蛋白表达；④与正常对照组相比，心肌炎阳性对照组心肌NF’KB的DNA结合活性增加5.6倍，15d-PGJ2和比格列酮治疗降低增强的NF.KB结合活性。⑤心肌炎阳性对照组心肌细胞核内NF-KB抑制物IKB蛋白含量明显降低；与心肌炎组相比，15d.PGJ，和比格列酮治疗分别增加IKB蛋白含量2.2和2.1倍。提示PPARγ配体治疗升高核内Iv：B水平而抑制NF。KB的活化。结论PPARγ配体治疗减轻自身免疫性心肌炎，其机制与诱导IKB表达、阻断NF.KB活化、抑制促炎细胞因子表达有关。