BACKGROUND Lingguizhugan decoction (LGZG), an ancient Chinese herbal formula, has been used to treat cardiovascular diseases in eastern Asia. We investigated whether LGZG has protective activity and the mechanism underlying its effect in an animal model of heart failure (HF). METHODS A rat model of HF was established by administering eight intraperitoneal injections of doxorubicin (DOX) (cumulative dose of 16 mg/kg) over a 4-week period. Subsequently, LGZG at 5, 10, and 15 mL/kg/d was administered to the rats intragastrically once daily for 4 weeks. The body weight, heart weight index (HWI), heart weight/tibia length ratio (HW/TL), and serum BNP level were investigated to assess the effect of LGZG on HF. Echocardiography was performed to investigate cardiac function, and H&E staining to visualize myocardial morphology. Myocardial ultrastructure and T-tubule-sarcoplasmic reticulum (TT-SR) junctions were observed by transmission electron microscopy. The JP-2 protein level was determined by Western blotting. The mRNA level of CACNA1S and RyR2 and the microRNA-24 (miR-24) level were assayed by quantitative RT-PCR. RESULTS Four weeks after DOX treatment, rats developed cardiac damage and exhibited a significantly increased BNP level compared with the control rats (169.6 ± 29.6 pg/mL versus 80.1 ± 9.8 pg/mL, P < 0.001). Conversely, LGZG, especially at the highest dose, markedly reduced the BNP level (93.8 ± 17.9 pg/mL, P < 0.001). Rats treated with DOX developed cardiac dysfunction, characterized by a strong decrease in left ventricular ejection fraction compared with the control (58.5 ± 8.7% versus 88.7 ± 4.0%; P < 0.001). Digoxin and LGZG improved cardiac dysfunction (79.6 ± 6.1%, 69.2 ± 2.5%, respectively) and preserved the left ventricular ejection fraction (77.9 ± 5.1, and 80.5 ± 4.9, respectively, P < 0.01). LGZG also improved the LVEDD, LVESD, and FS and eliminated ventricular hypertrophy, as indicated by decreased HWI and HW/TL ratio. LGZG attenuated morphological abnormalities and mitochondrial damage in the myocardium. In addition, a high dose of LGZG significantly downregulated the expression of miR-24 compared with that in DOX-treated rats (fold change 1.4 versus 3.4, P < 0.001), but upregulated the expression of JP-2 and antagonized DOX-induced T-tubule TT-SR microstructural remodeling. These activities improved periodic Ca2+ transients and cell contraction, which may underly the beneficial effect of LGZG on HF. CONCLUSIONS LGZG exerted beneficial effects on DOX-induced HF in rats, which were mediated in part by improved TT-SR microstructural remodeling.

中文翻译：

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灵桂竹肝汤可改善TT-SR的微观结构，减轻阿霉素引起的心力衰竭。

背景技术灵桂竹肝汤（LGZG）是一种古老的中草药配方，已被用于治疗东亚地区的心血管疾病。我们调查了LGZG是否具有保护活性以及其在心力衰竭（HF）动物模型中的作用机理。方法通过在4周的时间内进行八次腹腔注射阿霉素（DOX）（累积剂量为16 mg / kg），建立了HF大鼠模型。随后，每天一次以5mL，10mL和15mL / kg / d的LGZG胃内给药于大鼠，持续4周。研究了体重，心脏重量指数（HWI），心脏重量/胫骨长度比（HW / TL）和血清BNP水平，以评估LGZG对HF的影响。超声心动图检查心脏功能，H＆E染色可视化心肌形态。透射电镜观察心肌超微结构和T管-肌浆网（TT-SR）交界处。JP-2蛋白水平通过蛋白质印迹法确定。通过定量RT-PCR测定CACNA1S和RyR2的mRNA水平以及microRNA-24（miR-24）水平。结果DOX治疗后四周，与对照大鼠相比，大鼠出现了心脏损伤并表现出明显的BNP水平升高（169.6±29.6 pg / mL与80.1±9.8 pg / mL，P <0.001）。相反，尤其是在最高剂量下，LGZG显着降低了BNP水平（93.8±17.9 pg / mL，P <0.001）。用DOX治疗的大鼠出现心脏功能障碍，其特征是与对照组相比，左心室射血分数大大降低（58.5±8.7％对88.7±4.0％； P <0.001）。地高辛和LGZG可改善心脏功能障碍（分别为79.6±6.1％，69.2±2.5％）并保留左心室射血分数（分别为77.9±5.1和80.5±4.9，P <0.01）。LGZG还改善了LVEDD，LVESD和FS，并消除了心室肥大，如降低的HWI和HW / TL比所表明的。LGZG可减轻心肌的形态异常和线粒体损伤。另外，与DOX处理的大鼠相比，高剂量的LGZG显着下调了miR-24的表达（倍数变化1.4对3.4，P <0.001），但上调了JP-2的表达和拮抗DOX诱导的T管TT-SR的微结构重塑。这些活动改善了周期性的Ca2 +瞬变和细胞收缩，这可能是LGZG对HF的有益作用。