不同榖類為糖類來源對糖尿病老鼠體內氧化壓力、蛋白質糖化及脂質代謝的影響

Presentation on theme: "不同榖類為糖類來源對糖尿病老鼠體內氧化壓力、蛋白質糖化及脂質代謝的影響"— Presentation transcript:

1 不同榖類為糖類來源對糖尿病老鼠體內氧化壓力、蛋白質糖化及脂質代謝的影響
糖尿病患者因體內產生較多的自由基，並因體內抗氧化防禦系統能力的降低使得糖尿病患者體內的氧化壓力、蛋白質糖化均較正常人嚴重，再加上脂質代謝的不良是引發糖尿病併發症的主因。有許多的研究指出：糖尿病患者若血糖控制良好，可使患者體內的氧化壓力及蛋白質糖化作用降低。亦有研究指出：1.糖尿病患者食用amylose含量較高的澱粉類食物做為每日能量來源，有利於血糖的控制，2.不論正常或糖尿病受試者若食用米與小麥麵粉後，米有利於血糖的控制。本實驗即在探討餵予糖尿病老鼠玉米澱粉、三種不同品種米 (amylose含量不同) 及小麥麵粉後， 對糖尿病老鼠體內氧化壓力、蛋白質糖化及脂質代謝的影響。以AIN-76標準配方為控制組，以等比例不同品種的米，包括：秈米 (Indica rice, I組)、粳米 (Japonica rice, J組)、及糯米 (Waxy rice, W組) 做為碳水化合物的來源，並加入小麥麵粉 ( Wheat, H組) 及乾熱處理過的玉米澱粉 (cooked corn starch, C組) 兩組。實驗動物係採用雄性Wistar成鼠，體重 g，共54隻；分6組，每組9隻。以STZ (streptozotocin) 45 mg/kg對老鼠連續施予腹腔注射三天使誘發為糖尿病老鼠，當血糖達到270 mg/dL (約15 mmol/L) 後，判定為糖尿病老鼠。結果發現血液中的血糖、胰島素及果糖胺的值，正常老鼠與糖尿病老鼠有顯著的差異 (p  0.05)。之後開始進入實驗期，並餵予糖尿病老鼠各組實驗飲食，實驗期四週，實驗期結束犧牲老鼠取血液、肝臟及腎臟分析。蛋白質糖化以血液中的糖化血色素 (HbA1c) 及果糖胺 (fructosamine) 做為指標，氧化壓力以脂質過氧化物MDA (malondialdehyde) 的值及抗氧化防禦系統中的抗氧化酵素活性，及血液TRAP (total radicals-trapping antioxidant parameter) 值做為參考依據。結果發現，各組間肝臟中脂質過氧化物MDA的值以R及J組最低 ( p  0.05)，SOD (superoxide dismutase) 活性以J組最高 (22.13 ± 2.83 U/mg protein, p  0.05)。至於腎臟的(glutathione peroxidase) 以R、C、I、J、H組的活性最高 ( p  0.05)，SOD活性也是J組的活性最高 (13.65 ± 2.47 U/mg protein, p  0.05)；腎功能方面，也是以腎臟中抗氧化能力最高的J組較好 (血液中creatinine的值以J組最低，且具有顯著差異)。在血液的TRAP值方面，以J組最高 ( ± Μ, p  0.05)。在脂質代謝上，以I組在肝臟中膽固醇的值最低 (0.36 ± 0.05 mmol/L, p  0.05)，由以上結果得知，攝取粳米具有顯著降低糖尿病老鼠體內的氧化壓力，且氧化壓力的降低可延緩腎臟的損壞；秈米具有降肝臟膽固醇的功效。雖然W組的實驗飲食有較低含量的amylose，並會使得血糖控制較為不良，但在本實驗的結果中，W組除了在肝臟的氧化壓力較其他各組高，及餵食效率較其他各組低之外，與其他各組比較並無顯著差異。 關鍵字：糖尿病老鼠、米、抗氧化系統、氧化壓力、蛋白質糖化、直鍊澱粉。

2 The effects of using different cereals as carbohydrate sources on oxidative stress、glycation and lipid metabolism in diabetic rats Oxidative stress, glycation and lipid malmetabolism have been proposed to be linked and be increasing to tissue damage and the development of pathophysiology in diabetic patients. The purposed to evaluate the effects of using different cereals as carbohydrate source on oxidative status, protein glycation and lipid metabolism in diabetic rats. Fifty four male adult Wistar rats (b.w eq g) were divided into six groups: two control groups were AIN-76 diet, with or without 180 °C precooked corn starch, C and R groups respectivelly. Another 4 groups were matched with wheat flour (H group) and different variety rices (I group: Indica rice, J group: Japonica rice, W group: Waxy rice ). Diabetic rats were induced by injecting with 45 mg/kg/day streptozotocin in citrate buffer 3 days, continuously. While the blood sugar over 270 mg/dL (about 15 mmol/L) which was defined as the diabetic rats, and then feeding the different experimental diets. Four weeks later, the diabetic rats were sacrificed and sampled. The indicator of oxidative status and protein glycation were individually evaluated the activity of antioxidant enzyme/MDA (malondialdehyde) and the HbA1c/fructosamine. In addition, we also evaluated the plasma TRAP (total radicals-trapping antioxidant parameter) to elucidate the plasma antioxidant capacity of diabetic rats. Resulting, there is no significant difference between the experimental groups on HbA1c/fructosamine. The liver SOD (superoxide dismutase) activity is higher (22.13 ± 2.83 U/mg protein, p  0.05), and the MDA is lower (0.07 ± 0.01 nmol/ mg protein, p  0.05) in J group. The kidney SOD activity is higher (13.65 ± 2.47 U/mg protein, p  0.05), the plasma TRAP also the J group is the highest ( ± M, p  0.05). The cholesterol level in liver, is the I group lower (0.39 ± 0.05 mmol/L, p  0.05). Concluding, the Japonica rice is good to reduce oxidative stress and the Indica rice lowers the liver cholesterol level in diabetic rats. key word: diabetic rats, antioxidant system, oxidative stress, glycation.