新鮮小根蒜萃取物對於高果糖玉米糖漿誘導代謝紊亂及骨骼肌損傷之保護效應
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2023
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目的：高果糖玉米糖漿（HFCS；以55 %果糖和45 %葡萄糖組成）是近年來於飲品及加工食品中主要使用的添加糖。長期的高糖飲食不僅會引起代謝症候群，還會進一步導致骨骼肌異常。小根蒜（Allium macrostemon Bunge）是主要種植於台灣花蓮的藥食兩用傳統作物，通常經烹煮乾燥後作為中藥材使用，然而其新鮮鱗莖的生物活性功能尚待釐清。本研究旨在探討新鮮小根蒜萃取物對於高果糖玉米糖漿誘導的代謝失調和骨骼肌損傷的保護作用。材料和方法：製備新鮮小根蒜鱗莖的50 %乙醇萃取物（AMHE）。 將12週齡C57BL/6雄鼠隨機分為5組（CTL、HFCS、HFCS+AMHE250、HFCS+AMHE500、HEE500），供其自由攝食一般飼料和飲用二次水或30% HFCS溶液，AMHE（劑量250 和 500 mg/kg）則每日以管餵方式補充，實驗為期14週。於實驗中測試了胰島素敏感性、空腹血糖值、血壓、血清三酸甘油酯、血清總膽固醇濃度和運動表現能力。另外，將腓腸肌進行組織橫切面面積、氧化壓力、粒線體活性和數量的分析。 在體外試驗模式，C2C12 肌母細胞經分化4 天成肌管細胞，隨後肌管細胞以不同HFCS濃度（20、40或80 mM）處理4 天並於最末2天合併處理80 nM胰島素。試驗AMHE（125、250或500 μg/ml）在HFCS誘導肌細胞損傷的保護效果。 並於腓腸肌組織及肌管細胞中進行分子機制的探討。結果：HFCS使小鼠增加體重、胰島素阻抗、高血壓及血脂異常，並降低運動表現。AMHE的補充對於HFCS造成的傷害具有保護效益，而AMHE500又優於AMHE250。在腓腸肌中，發現HFCS 導致肌肉萎縮、氧化壓力堆積和粒線體功能失調。二氫乙啶（DHE）染色和琥珀酸脫氫酶（SDH）染色分析結果表明，AMHE500具有顯著的抗氧化能力，並透過增加粒線體酵素活性來增強粒線體功能。蛋白質表現量的改變也顯示出相同的結果，AMHE500降低肌肉萎縮（MuRF1、MAFbx）和促氧化（NOX2/4）蛋白質的表達，並提高抗氧化（SIRT3、FOXO3A、SOD2、Catalase）、粒線體功能（PGC-1α、COX IV）相關蛋白質的表現。 最後建立以HFCS合併胰島素誘導的C2C12肌管細胞代謝紊亂及損傷模式，結果顯示AMHE（125、250 或 500 μg/ml）在暴露於胰島素的 C2C12 肌管細胞中呈現劑量效應回復 HFCS 引起的肌細胞損傷。結論：綜上所述，AMHE 可能透過 CREB/PGC1-α/SIRT3 訊息路徑增強抗氧化能力和粒線體功能，從而有效減輕過量 HFCS 攝取導致代謝失調相關的骨骼肌損傷和運動表現下降。這些結果對於未來AMHE 針對 HFCS 所引起的損傷治療功能奠定了基礎。
Aims: High-fructose corn syrup (HFCS, which contains 55 % fructose and 45 % glucose) is the major added sugar, especially in beverages and manufactured foods in recent years. Chronic high-sugar diet not only causes metabolic syndrome, but also further leads to skeletal muscle abnormalities. Allium macrostemon Bunge (AM) is a medicinal and edible traditional crop mainly growth in Hualien, Taiwan. It is often used as the herbal medicine after boiled and dried out, however, its fresh bulbs' bioactive function is unclear. This study aimed to explore the protective effects of AM extract against high-fructose corn syrup (HFCS)-induced metabolic dysregulation and skeletal muscle damage. Materials and Methods: The hydro-ethanolic extract of fresh AM bulb (AMHE; AM 50 % ethanol extract) was prepared. 12-week old C57BL/6 male mice were randomly divided into five groups (CTL, HFCS, HFCS+AMHE250, HFCS+AMHE500, HEE500). Mice were given ad libitum access to food and water or 30 % HFCS for 14 weeks. AMHE (250 and 500 mg/kg) were administered by oral gavage daily. Insulin sensitivity, fasting blood sugar, blood pressure, serum triglycerides, total cholesterol levels and exercise performance were examined. Muscle mass, cross-section area, oxidative stress, mitochondrial activity and number were analyzed in gastrocnemius. C2C12 myoblasts were differentiated to myotubes for 4 days. Myotubes were then treated 4 days with different concentrations of HFCS (20, 40 or 80 mM) combined with 80 nM insulin for the last 2 days. The protective effects of AMHE (125, 250 or 500 μg/ml) on HFCS-induced damages were examined. The molecular mechanisms inside gastrocnemius tissue and myotubes were studied.Results: Body weight gain, insulin resistance, hypertension, and dyslipidemia were increased in mice fed with HFCS, but exercise performance was decreased. AMHE had protective effects against HFCS-induced damages, while the effect of AMHE500 was better than AMHE250. In gastrocnemius, HFCS contributed to muscle atrophy, oxidative stress accumulation and mitochondrial dysfunction. The results from dihydroethidium (DHE) staining and succinate dehydrogenase (SDH) staining analysis revealed that AMHE500 had notable anti-oxidant ability and enhanced the mitochondrial function by increasing mitochondrial enzyme activity. The alteration of protein levels also showed the same results, which AMHE500 downregulated protein expression of muscle atrophy (MuRF1, MAFbx) and pro-oxidation (NOX2/4), and upregulated protein levels of anti-oxidation (SIRT3, FOXO3A, SOD2, catalase), mitochondrial function (PGC-1α, COX IV). AMHE (125, 250, or 500 μg/ml) also expressed the dose dependent effect to reverse muscle cell damages caused by HFCS in C2C12 myotubes exposed to insulin.Conclusion: Taken together, AMHE had the effectiveness in mitigating metabolic dysregulation-associated skeletal muscle damages and decreased exercise performance with excess HFCS consumption, by enhancing antioxidant ability and mitochondrial function through possibly CREB/PGC1-α/SIRT3 signaling pathway. These results provided a foundation to the therapeutic function of AMHE against HFCS-induced damages in the future.
Aims: High-fructose corn syrup (HFCS, which contains 55 % fructose and 45 % glucose) is the major added sugar, especially in beverages and manufactured foods in recent years. Chronic high-sugar diet not only causes metabolic syndrome, but also further leads to skeletal muscle abnormalities. Allium macrostemon Bunge (AM) is a medicinal and edible traditional crop mainly growth in Hualien, Taiwan. It is often used as the herbal medicine after boiled and dried out, however, its fresh bulbs' bioactive function is unclear. This study aimed to explore the protective effects of AM extract against high-fructose corn syrup (HFCS)-induced metabolic dysregulation and skeletal muscle damage. Materials and Methods: The hydro-ethanolic extract of fresh AM bulb (AMHE; AM 50 % ethanol extract) was prepared. 12-week old C57BL/6 male mice were randomly divided into five groups (CTL, HFCS, HFCS+AMHE250, HFCS+AMHE500, HEE500). Mice were given ad libitum access to food and water or 30 % HFCS for 14 weeks. AMHE (250 and 500 mg/kg) were administered by oral gavage daily. Insulin sensitivity, fasting blood sugar, blood pressure, serum triglycerides, total cholesterol levels and exercise performance were examined. Muscle mass, cross-section area, oxidative stress, mitochondrial activity and number were analyzed in gastrocnemius. C2C12 myoblasts were differentiated to myotubes for 4 days. Myotubes were then treated 4 days with different concentrations of HFCS (20, 40 or 80 mM) combined with 80 nM insulin for the last 2 days. The protective effects of AMHE (125, 250 or 500 μg/ml) on HFCS-induced damages were examined. The molecular mechanisms inside gastrocnemius tissue and myotubes were studied.Results: Body weight gain, insulin resistance, hypertension, and dyslipidemia were increased in mice fed with HFCS, but exercise performance was decreased. AMHE had protective effects against HFCS-induced damages, while the effect of AMHE500 was better than AMHE250. In gastrocnemius, HFCS contributed to muscle atrophy, oxidative stress accumulation and mitochondrial dysfunction. The results from dihydroethidium (DHE) staining and succinate dehydrogenase (SDH) staining analysis revealed that AMHE500 had notable anti-oxidant ability and enhanced the mitochondrial function by increasing mitochondrial enzyme activity. The alteration of protein levels also showed the same results, which AMHE500 downregulated protein expression of muscle atrophy (MuRF1, MAFbx) and pro-oxidation (NOX2/4), and upregulated protein levels of anti-oxidation (SIRT3, FOXO3A, SOD2, catalase), mitochondrial function (PGC-1α, COX IV). AMHE (125, 250, or 500 μg/ml) also expressed the dose dependent effect to reverse muscle cell damages caused by HFCS in C2C12 myotubes exposed to insulin.Conclusion: Taken together, AMHE had the effectiveness in mitigating metabolic dysregulation-associated skeletal muscle damages and decreased exercise performance with excess HFCS consumption, by enhancing antioxidant ability and mitochondrial function through possibly CREB/PGC1-α/SIRT3 signaling pathway. These results provided a foundation to the therapeutic function of AMHE against HFCS-induced damages in the future.
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小根蒜, 高果糖玉米糖漿, 代謝紊亂, 肌肉萎縮, 氧化壓力, 粒線體功能, Allium macrostemon Bunge, High-fructose corn syrup, Metabolic disorder, Muscle atrophy, Oxidative stress, Mitochondrial function