黃芩素對於血管鈣化及心臟肥厚之保護機轉

Protective mechanisms of baicalein on vascular calcification and cardiac hypertrophy

李姒蓉(Szu-Jung Lee)

指導教授 ： 葉竹來

高雄醫學大學/醫學院/醫學研究所碩士班/碩士(2019年)

摘要

血管鈣化的發生通常伴隨著血管併發症，例如動脈粥樣硬化、糖尿病和慢性腎病，以及顯著的心血管發病率和死亡率。血管平滑肌細胞凋亡是血管鈣化的關鍵角色，其導致血管壁硬化並降低收縮功能。過去的研究已經證實黃芩 （Scutellaria baicalensis Georgi） 的主要天然黃酮類化合物黃芩素（5,6,7-trihydroxy-2-phenyl-4H-1‒ benzopyran-4-one, baicalein），具有抗氧化、抗發炎、抗血栓、抗病毒和抗癌等多種生物活性，文獻報告也指出黃芩素在肺動脈高血壓和心肌病變等心血管疾病中具有保護的作用。因此本研究目的是探討黃芩素在血管平滑肌細胞和維生素 D3 併用尼古丁處理大鼠之血管鈣化及心臟肥大的保護機轉。
在體外實驗，大鼠胸主動脈的血管平滑肌細胞以 baicalein 前處理 1 小時，再加入 10 mM β-GP 培養 48 小時或 10 天，進行測定血管鈣化的相關實驗。在活體實驗，維生素 D3 和尼古丁被用來誘導大鼠血管鈣化及心臟肥大， baicalein 做為治療藥物並每兩日給予一次，再使用穿透式心臟超音波儀器測得每隻大鼠的心臟功能參數。
我們發現透過 Alizarin Red S 染色、鈣離子沉積、鹼性磷酸酶 (ALP) 活性測試後， baicalein 可以抑制 β-GP 所引起的細胞凋亡及血管鈣化。流式細胞儀 Annexin V/PI 雙染測定中，治療組細胞凋亡數目少於誘導組，顯示出 baicalein 也能抑制血管平滑肌細胞的凋亡。西方墨點法和免疫螢光的結果顯示， baicalein 能提升 SM22-α 和 α-SMA 的表現，並抑制 Runx2 和 BMP-2 的表現。動物實驗結果， baicalein 抑制維生素 D3 併用尼古丁誘導的心臟肥大，減少心臟及體重比率。心臟超音波顯示 baicalein 可改善左心室功能。
綜上所述， baicalein 藉由防止細胞凋亡、降低成骨化表現和提升收縮功能表現來減少 β-GP 誘導的血管鈣化。 此外， baicalein 具有抑制心臟肥大和增加心臟功能的作用。依據實驗結果， baicalein 可能在血管鈣化和相關的心血管疾病中具有治療用途。

關鍵字

黃芩素 ； β-甘油磷酸鹽 ； 血管鈣化 ； 平滑肌細胞 ； 尼古丁 ； 維生素D3

並列摘要

The occurrence of vascular calcification is often accompanied by overlapping vascular complications such as atherosclerosis, diabetes and chronic kidney disease, as well as significantly increase cardiovascular morbidity and mortality. Apoptosis of vascular smooth muscle cells play an important role in vascular calcification, which leads to stiffen of the vessel wall and reduce the contractile function. Previous studies have confirmed that baicalein is the main natural flavonoid of Scutellaria baicalensis Georgi rhizome, which has many biological activities such as anti-oxidation, anti-inflammatory, anti-thrombotic, anti-viral and anti-cancer. Baicalein has protective effects in cardiovascular diseases, including pulmonary hypertension and cardiomyopathy. Therefore, the purpose of the present study was to investigate the protective mechanisms of baicalein on vascular calcification and cardiac hypertrophy in vascular smooth muscle cells and vitamin D3 plus nicotine treated rats.
In vitro study, vascular smooth muscle cells from the thoracic aorta of rats were pretreated with baicalein for 1 hour, and then added with 10 mM β-glycerolphosphate (β-GP) for 48 hours or 10 days. Then, an experiment for measuring vascular calcification was performed. In vivo study, vitamin D3 plus nicotine were used to induce vascular calcification and cardiac hypertrophy in rats, baicalein as a therapeutic drug and every two days. Cardiac function parameters were measured using a penetrating cardiac ultrasound instrument.
We found that baicalein inhibited apoptosis and vascular calcification induced by β-GP after being tested by Alizarin Red S staining, calcium deposition, and alkaline phosphatase (ALP) activity. Flow cytometry Annexin V/PI double staining assay showed that the number of apoptosis in the treatment group was lower than the inducer group, indicating that baicalein also inhibited apoptosis of vascular smooth muscle cells. The results of the Western blot and immunofluorescence show that baicalein can enhance the performance of SM22α and α-SMA and inhibit the performance of BMP-2 and Runx2. In the animal experiments, baicalein attenuated vitamin D3 plus nicotine induced cardiac hypertrophy, indicated by an decreased heart weight/body weight ratio. Echocardiography showed that baicalein improved left ventricular function.
In conclusion, baicalein attenuated β-GP-induced vascular calcification by preventing apoptosis, down-regulated osteogenic phenotype and up-regulated contractile phenotype. In addition, baicalein has the potential effect to inhibit cardiac hypertrophy and increase the heart function. Based on our results, baicalein may be a therapeutic role in the treatment of vascular calcification and relative cardiovascular diseases.

並列關鍵字

Baicalein ； β-glycerolphosphate ； vascular calcification ； smooth muscle cell ； nicotine ； vitamin D3

參考文獻

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