School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China; Department of Experimental Animals, Zhejiang Academy of Traditional Chinese Medicine, Hangzhou, 310012, China.
School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China.
J Ethnopharmacol. 2022 Jun 28;292:115213. doi: 10.1016/j.jep.2022.115213. Epub 2022 Mar 21.
Smilax glabra Roxb., the dry rhizome of Sarsaparilla, which is also known as Tu fuling (TFL) in China, is a well-known traditional CHINESE medicine that is widely used for detoxication, relieving dampness and as a diuretic. We have previously shown that the extracted TFL flavonoids (designated TFLF) possess anti-cardiac hypertrophy effects in vitro. However, the anti-cardiac hypertrophy effects of TFLF in vivo and the underlying mechanisms remain to be elucidated.
To reveal the underlying therapeutic mechanism of TFLF on cardiac hypertrophy by using transverse aortic constriction (TAC) model and cellular assays in vitro.
MATERIAL & METHODS: Cardiac hypertrophy was replicated by TAC surgery in rats or by isoprenaline treatment of rat H9C2 myocardial cells in vitro. Cardiac structure and function were evaluated by echocardiographic and hemodynamic examinations in vivo and histological analysis of tissues ex vivo. Biochemical kits and quantitative PCR were used to analyze markers of cardiac hypertrophy. Expression and phosphorylation of key proteins in the Raf/MEK/ERK pathway were quantified by Western blotting. We further confirmed our findings in H9C2 rat cardiomyocytes treated with isoprenaline and the ERK inhibitor in vitro.
TFLF attenuated cardiac hypertrophy and fibrosis and improved cardiac dysfunction in TAC rats. TFLF treatment induced a strong reduction in serum NT-proBNP levels. Cardiac hypertrophy marker gene (ANP, BNP and β-MHC) expression and the phosphorylation levels of c-Raf and ERK1/2 were decreased by TFLF treatment. TFLF also protected H9C2 cells from isoprenaline-induced hypertrophy in vitro via a similar molecular mechanism as that observed in the rat heart. Moreover, pretreatment with TRLF and the ERK inhibitor further inhibited the mRNA overexpression of hypertrophic genes in vitro.
TFLFs may protect against pathological cardiac hypertrophy via negative regulation of the Raf/MEK/ERK pathway. Thus, TFLFs are implicated as a potential pharmacological agent for treating cardiac hypertrophy in clinical practice.
菝葜（Smilax glabra Roxb.），菝葜科植物，其干燥根茎在中国又被称为土茯苓（TFL），是一种广为人知的传统中药，具有解毒、祛湿和利尿的功效。我们之前已经证明，提取的菝葜类黄酮（命名为 TFLF）在体外具有抗心肌肥厚的作用。然而，TFLF 在体内的抗心肌肥厚作用及其潜在机制仍有待阐明。
通过横主动脉缩窄（TAC）模型和体外细胞实验，揭示 TFLF 对心肌肥厚的潜在治疗机制。
通过 TAC 手术在大鼠体内或异丙肾上腺素处理大鼠 H9C2 心肌细胞在体外复制心肌肥厚模型。通过体内超声心动图和血流动力学检查以及组织学分析评估心脏结构和功能。生化试剂盒和定量 PCR 用于分析心肌肥厚标志物。通过 Western blot 定量分析 Raf/MEK/ERK 通路中的关键蛋白的表达和磷酸化。我们进一步在体外用异丙肾上腺素和 ERK 抑制剂处理 H9C2 大鼠心肌细胞中证实了我们的发现。
TFLF 可减轻 TAC 大鼠的心肌肥厚和纤维化，改善心功能障碍。TFLF 治疗可显著降低血清 NT-proBNP 水平。TFLF 处理可降低心肌肥厚标志物基因（ANP、BNP 和 β-MHC）的表达和 c-Raf 和 ERK1/2 的磷酸化水平。TFLF 还通过类似的分子机制，在体外保护 H9C2 细胞免受异丙肾上腺素诱导的肥大。此外，TFLF 和 ERK 抑制剂预处理进一步抑制了体外肥厚基因的 mRNA 过表达。
TFLF 通过负调控 Raf/MEK/ERK 通路可能对病理性心肌肥厚起到保护作用。因此，TFLF 被认为是临床治疗心肌肥厚的潜在药物。
