高、低分子量幾丁聚醣對由 Streptozotocin 及 Nicotinamide 所誘發之糖尿病大鼠血膽固醇、 血糖及脂肪細胞激素的影響   全文下載

Effects of High and Low Molecular Weight Chitosan on Plasma Cholesterol, Glucose and Adipocytokines in Diabetic Rats Induced by Streptozotocin and Nicotinamide

幾丁聚醣具有降低脂肪作用。為了比較高、低分子量幾丁聚醣對血糖、血膽固醇及脂肪細胞激素的影響，雄性Sprague-Dawley大鼠分成四組：正常組、糖尿病組、糖尿病餵食高分子或低分子量幾丁聚醣組，實驗共進行七週。糖尿病組是經由皮下注射Streptozotocin 及Nicotinamide 所誘發。實驗結果發現相對於餵食正常組飲食，糖尿病大鼠餵食高分子量幾丁聚醣會降低肝臟重量及腹腔脂肪組織重量。糖尿病大鼠餵食兩種分子量幾丁聚醣會增加糞便三酸甘油酯及膽固醇排除，降低肝臟膽固醇及三酸甘油酯含量，這種現象在高分子量幾丁聚醣組更加明顯。高分子量而非低分子量幾丁聚醣餵食會明顯降低糖尿病大鼠血漿果糖胺、瘦體素、總膽固醇並降低胰島素阻抗指數。高分子量幾丁聚醣會降低糖尿病大鼠小腸雙糖?包含蔗糖?及乳糖?。此外，兩種分子量幾丁聚醣皆會將低血漿中tumor necrosis factor-alpha以及plasminogen activator inhibitor-1濃度。由結果推測餵食高分子量幾丁聚醣可能會藉由降低糖尿病大鼠肝臟及脂肪組織中脂質的堆積及改善慢性發炎來降低胰島素阻抗。高分子量幾丁聚醣改善糖尿病大鼠之糖代謝與脂質代謝可能比低分子量幾丁聚醣更加明顯。

Chitosan is known for its lipid-lowering effect. To investigate the comparative effects of low (LCS) and high molecular weight chitosan (HCS) on plasma glucose, cholesterol and adipocytokines, male Sprague-Dawley rats were divided into four groups: normal control, diabetic, and diabetic fed the HCS or LCS diet for seven weeks. Diabetes was induced by subcutaneous injection of nicotinamide and streptozotocin. Results showed that diabetic rats fed the HCS diet had reduced liver weight and perirenal adipose weight, compared to those that were fed the control diet. Higher fecal triglyceride and cholesterol excretion and lower hepatic cholesterol and triglyceride contents were found in diabetic rats fed with both chitosan diets. These observations were more significant in the HCS group than in the LCS group. HCS, but not LCS diet, significantly reduced plasma fructosamine, leptin, total cholesterol and lowered the insulin resistance index (homeostasis model assessment; HOMA) in diabetic rats. A lower intestinal dissaccharidase activity including sucrase and lactase was found in diabetic rats fed the HCS diet. Moreover, plasma tumor necrosis factor-alpha and plasminogen activator inhibitor-1 concentra-tions were significantly reduced by both chitosan supplementations. The results suggested that HCS feeding may reduce insulin resistance by the suppression of lipid accumulation in liver and adipose tissue and amelioration of chronic inflammation in diabetic rats. HCS may improve glucose and lipid metabolism more significantly than LCS in diabetic rats.