探討芝麻油體之生物性包埋乳酸菌對降低血中膽固醇之影響

Abstract

心血管疾病中冠狀動脈硬化為主要的致死原因。醫學調查顯示，心血管疾病的發生率與血液中總膽固醇及低密度脂蛋白(LDL)膽固醇的濃度具有正相關性，而特定之乳酸菌:如保加利亞桿菌(Lactobacillus delbrueckii ssp. Bulgaricus)則有降低血脂之功效，但若直接進食會因動物消化道之胃酸及膽鹽，而導致乳酸菌存活率明顯降低。經實驗室先前研究巳知，利用芝麻油體包埋乳酸菌，顯著提高乳酸菌於酸性及膽鹽的逆境條件下之存活率。本試驗擬探討食用經此技術包埋之乳酸菌對動物體內血脂之影響。 以八週齡大SD公鼠為試驗動物，連續6週餵食正常飲食、高膽固醇飲食以及經油體包埋或未包埋之乳酸菌。每7天進行大鼠尾部靜脈血液採集，取得血清測試血中總膽固醇、高密度脂蛋白、低密度脂蛋白以及三酸甘油脂等臨床生化值。 實驗結果顯示，高膽固醇飲食給予確實可誘導實驗鼠血脂值上升；而經餵食高菌量乳酸菌後，血脂值則有下降現象。另外，低菌量之乳酸菌無法通過腸道進而達到有效降低血脂之功效；然而，經由油體包埋低菌量乳酸菌經口餵食後，即可有效降低血中脂質含量，顯示芝麻油體確實可作為生物性包埋，提供保護特定乳酸菌定殖於腸道，進而達到降低血膽固醇之功效。

Atherosclerosis is one of the primary causes of heart diseases and stroke. The complications of atherosclerosis often lead to death. Prospective studies showed the risk of cardiac morbidity and mortality are directly related to total or low-density lipoprotein cholesterol of plasma. The specific lacto acid bacteria, for example, Lactobacillus delbrueckii ssp. Bulgaricus had an efficiency to decrease plasma cholesterol. However, the probiotics couldn’t survive in sufficient number through high-acid or bile salt in gastrointestinal tract. Based on previous studies, artificial sesame oil emulsion encapsulation of bacteria could increase (approximately 104 time) the survival rate when subjected to simulate high-acid milieu. The purpose of this study is find evidences that, in vivo efficiency, biocapsule technique for encapsulation of bacteria could lead to decrease plasma cholesterol. The animal models of SD rats were obtained at the ages of eight weeks. Blood samples were collected from the tail ventral on every seven days and analyzed for total cholesterol、low-density lipoprotein、high-density lipoprotein and triacylglycerol. Results show the SD rats had a significant increase on plasma cholesterol after feeding cholesterol-enriched diets in the forth week. However, the plasma cholesterol level was decreased by feeding sesame oil encapsulated with bacteria, less effectiveness was observed by feeding with lacto acid bacteria only. Furthermore, both of the plasma triacylglycerol and low-density lipoprotein have decreased after feeding with lacto acid bacteria, and the high-density lipoprotein is higher than that only by cholesterol-enriched diet in rat. Both concentrations of 1×107、1×108 CFU/day and 1×109 CFU/day of bacteria have the same effect. Therefore, the artificial sesame oil emulsion may serve as an effective biocapsule for encapsulation of bacteria to decrease plasma cholesterol.