| 摘要: | 老化為生物生理功能衰退的現象，目前認為老化會導致心室收縮異常(QT 間期及動作電位平台 期延長)、心臟肥大、心臟與肌肉的纖維化，以及肌肉的流失，但其機轉尚待釐清。根據預實驗，老 化小鼠餵食褐藻醣膠後，因老化導致的心臟電訊號異常有得到改善；可從免疫化學組織染色結果發 現對於心臟肥大、心臟與肌肉纖維化亦能改善。在我們的研究計畫中，將會分為三個研究目標進行 探討。目標一：根據預實驗的結果探討因老化引起心臟及肌肉的功能異常，並觀察餵食褐藻素及合 併褐藻醣膠及褐藻素後，心臟及肌肉功能異常的改善效果。目標二：研究因老化會引起心臟及肌肉 的功能異常的機制，測定HCN、LTCCs 離子通道對於QT 延長的調控；除探討TGF-β 訊息傳遞路徑 (Smad-dependent/Smad-independent pathway)下游基因和老化的關係外，利用metacore 的database 預 測以TGF-β 為主與老化相關的基因調控機制(potential pathway network)。目標三：以餵食褐藻醣膠老 化小鼠的代謝產物(血液、尿液、心臟及肌肉的組織勻漿液)分析結果為基礎，利用質譜儀及其分析 軟體(Progenesis QI)分析餵食褐藻素及兩者合併補充後其代謝產物的組成成分(PCA、S-plot 圖)；另外 利用分析軟體Unifi 分析其機能性成分，以Vitamin C 作為對照組，找出除褐藻醣膠及褐藻素以外， 對老化有改善效果的成分。
Aging is a phenomenon of physiological function decline, which will cause abnormal cardiac/muscular electrophysiologies and structral remodeling. Aging is currently thought can cause ventricular contraction abnormalities (QT and the plateau phase prolongation), cardiac hypertrophy, cardiac/muscular fibrosis, and the loss of muscle. However, the mechanisms are still unknown. We previously use young (8-week-old) mice as control group, to measure the ECG of aging mice (2-year-old) and aging mice which were fed fucoidan. The results confirmed the abnormal electrical signals were caused by aging of the heart. Besides, immunochemical staining was used to observe cardiac hypertrophy, cardiac/muscular fibrosis, and the degree of muscular loss. All the results showed that after feeding fucoidan, the abnormal cardiac/muscular electrophysiologies and structural remodeling would be resue. In our current project, we will investigate the abnormal cardiac/muscular electrophysiologies and structural remodeling and their mechanisms. Then use fucoidan and fucoxanthin as examples to develop the therapeutics from brown algae. Specifically, we propose in Specific Aim 1: To establish the aging mice model to investigate abnormal cardiac/muscular electrophysiologies (QT/the plateau phase prolongation) and structural remodeling (hypertrophy or fibrosis). Base on our previously preliminary data from 3 groups (8-week-old control、 2-year-old mice and aging mice treat with fucoidan), to confirm the effect after feeding fucoxanthin, mixture of fucoidan and fucoxanthin in rescuing the abnormal cardiac/muscular electrophysiologies (ECG and action potential measurement) and structural remodeling (grip strength, exhaustive swimming time and immunochemical staining). Specific Aim 2: To investigate the mechanisms of abnormal cardiac and muscular electrophysiologies (patch clamp) cause by aging by electrocardiogram and biochemistry analysis (i.e. western blot, co-immunoprecipitation, confocal fluorescent imaging). First, we will observe the expression level and gating property of HCN2 and LTCC by patch clamp. Second, using co-immunoprecipitation to indentify 1) the association of HCN2 and its tyrosine phosphorylation, 2) the inactivation between CaM and IQ motif of LTCC. In addition, we will focus on the Smad-dependent/Smad-independent pathway related to TFG-β which would affect cardiac hypertrophy/fibrosis; then use metacore to find other possible downstream genes, such as FGF2 and MMP-9 (according to previous study, MMP-9 could inhibit cancer cell proliferation and cause cardiac hypertrophy/fibrosis). Specific Aim 3: Base on the preliminary data from fucoidan, to establish a screening platform and identify novel therapeutic agents of aging. We will use ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Xevo G2-S Q-Tof) to analysis the metabonomics after feeding fucoxanthin and mixture of fucoidan and fucoxanthin. Then use vitamin C as a positive control to indentify functional compounds in brown algae other than fucoidan and fucoxanthin. We hope our present studies would elucidate the various mechanisms of abnormal cardiac/muscular electrophysiologies and structural remodeling cause by aging. In addition, we also would like to explore the new functional components which will work on the rescue of those abnormal electrophysiologies and structural remodeling caused by aging. |
