| 摘要: | 文獻中對於在肥胖鼠模式中，心臟肥大重塑、凋亡、走向纖維化的過程以及救援途徑等等均有所研究，然而卻鮮有針對肥胖與老化共同對於心臟細胞影響及機轉的分子研究成果。是故本研究之目的係評估老化與肥胖這兩個因子共同作用下，心臟心肌細胞之肥大、凋亡、纖維化以及引發救援途徑等過程，其胞內的訊遞機轉及分子相互間之關聯性。實驗設計上係利用基因轉殖大鼠(Zucker鼠)動物模式，分為四大組進行研究，致分為年輕瘦(YL；Control, 11隻)、年輕胖 (YO, 10隻)、老化瘦(OL, 11隻)、老化胖(OO, 11隻)的Zucker鼠，其中年齡之定義為年輕(四個月)與年老(十四個月)。各組分別觀察其心臟左心室型態及細部的特徵以作為心臟功能的初步指標，並探討其心肌細胞有關肥大、凋亡、纖維化之蛋白表現以及相關之訊遞途徑。本篇運用之實驗技術包括組織切片以觀察組織型態(H&E stain)、細胞凋亡試驗(TUNEL assays)、纖維化試驗(Trichrome stain) 、西方墨漬法(Western blotting)以及核質分離試驗來反覆驗證。實驗的結果顯示，在全心重、正常心肌骨架，心臟肥大指標(ANP, BNP)及相關蛋白訊遞(IL-6, STAT3, Calcineurin, NFATc3)途徑，以及細胞凋亡試驗、心肌細胞死亡接受器(Fas Receptor)依賴型凋亡途徑等凋亡路徑，纖維化觀察及纖維化途徑(FGF2, uPA, PAI-1)、(MMP9、TIMP1) 與(TGF-?牷BMEK1、SP1、CTGF)等纖維化指標，在與YL組相比較下，YO、OL 和OO等組皆有顯著性的差異。若以年齡上的分組來進行比較，我們發現年齡大的比年齡小的有較高的蛋白表現量，且在YO及OO兩組較老化的組別中，兩組間並無顯著的差異。總言之，肥胖加上老化會共同促進心臟肥大、心肌死亡(經驗證係經由接受器依賴型凋亡途徑及粒線體依賴型凋亡途徑)、纖維化及心肌救援途徑之活化，以上的發現提供了肥胖加上老化共同作用而加速誘發心臟衰竭之可能機制。
Cardiac Remodeling hypertrophy, apoptotic, fibrosis and survival signalings were involved in obesity, but details regarding the cardiac molecular mechanism in the aging effect in obesity were not available. The purpose of this study was to evaluate whether the aging obesity will additively influence the hypertrophic, apoptotic, fibrotic and survival pathways. Eleven young lean (YL), 10 young obese (YO), 11 old lean (OL), and 11 old obese (OO) Zucker rats were investigated at 4 and 14 months old. The cardiac characteristics, apoptotic, hypertrophic, and fibrosis level and their related pathways in the excised left ventricle form rats were measured by heart index, histological analysis, positive TUNEL assays, H&E stain, Trichrome stain, Western blotting. The preliminary results showed that compared with YL group, the whole heart weight, the abnormal myocardial architecture, hypertrophic markers (ANP, BNP), hypertrophic-related pathways (IL6, STAT3, Calcineurin, NFATc3) and TUNEL-positive apoptotic cells, as well as the activity of cardiac Fas receptor-dependent apoptotic pathway (Fas/L, Fas, FADD, caspase-8, tBid, caspase-3 cytosolic cytochrome c, caspase-9, caspase-3) and, fibrosis-related pathways (FGF2, uPA,PAI-1),(MMP9,TIMP1) and (TGF-b, MEK1, SP1, CTGF) and Trichron-positive fibrotic cells and, Lipid metabolism-related pathways (AMPK, PPAR??, PPAR??)were significantly higher expressed in YO, OL or OO groups. These pathways were then higher expressed in OO group compared with YO or OL groups. The cardiac hypertrophic level, Fas receptor-dependent apoptotic pathways, fibrosis, lipid metabolism and cell signalings were further activated in the aging obesity. These findings may provide a possible mechanism for developing heart failure in aging obesity |
