乳酸桿菌 GR0877 對葡聚糖硫酸鈉導致腸道炎症小鼠模式的預防作用

Abstract

過去認為母乳是無菌的，但後來發現母乳中具有乳酸菌 (lactic acid bacteria, LAB) 的存在，乳酸菌中的乳桿菌屬 (Lactobacillus) 是最常見的菌屬，且目前許多的研究發現乳汁中除了擁有乳桿菌屬外，還有雙歧桿菌屬 (Bifidobacterium)、葡萄球菌屬 (Staphylococcus)、擬桿菌屬 (Bacteroides)、梭菌屬 (Clostridium) 及腸球菌 (Enterococcus) 等等，不過母乳中菌屬會隨著不同族群以及女性個體差異會有所不同。有很多證據顯示，乳酸桿菌具有抗發炎的效果，且也有研究指出乳酸桿菌對於哺乳女性以及健康兒童有正面的影響，使得乳酸桿菌成為益生菌的新目標。本次研究想要探討乳酸桿菌的益生特性，使用葡聚糖硫酸鈉 (dextran sodium sulfate, DSS) 誘導小鼠產生潰瘍性結腸炎，使用乳酸桿菌來評估改善腸道發炎的效果。本次實驗挑選過去實驗室利用細胞模式篩選出來的乳酸桿菌，本研究利用該乳酸桿菌使用於潰瘍性結腸炎的動物模式，將乳酸桿菌分為活菌以及熱殺菌，探討兩種母乳酸桿菌預防與改善腸道發炎的能力。實驗結果顯示，餵食熱殺菌的實驗小鼠，糞便潛血、結腸長度與糞便型態均有顯著改善，而餵食活菌的實驗小鼠，在糞便潛血與糞便型態有顯著改善，進一步組織學分析發現餵食母乳酸桿菌的腸壁完整性、細胞浸潤、潰瘍等等均有改善，腸道組織的緊密連接 (tight junction) 相關分子也有受到改善的情形。藉由以上結果得知，該乳酸桿菌對於緩解腸道發炎症狀具有良好的預防效果，未來可作為在探討益生菌對於腸道發炎的相關研究，並且具有可應用於舒緩臨床潰瘍性結腸炎患者的潛力。

In the past, breast milk was considered sterile, but the presence of lactic acid bacteria (LAB) in breast milk was found in healthy women later, and now multiple genera have been found in breast milk in many studies. At present, there are a lot of evidence suggest that lactic acid bacteria have anti-inflammatory effects, and some studies have also pointed out that breast milk bacteria have positive impacts on breastfeeding women and healthy children, making breast milk bacteria a new target for probiotics. This study aimed to investigate the probiotic properties of human milk bacteria on ulcerative colitis in mice induced using dextran sodium sulfate (DSS). The ability of human milk bacteria in improving intestinal inflammation was evaluated.In this experiment, the breast milk bacteria screened by the laboratory using cell models in the past was applied to the animal model of ulcerative colitis. Both live and heat sterilized bacteria were explored their ability in ameliorating intestinal inflammation. The experimental results showed that the fecal occult blood, colon length, and feces pattern were significantly improved in the ulcerative colitis mice fed with heat-killed bacteria, while the fecal occult blood and feces pattern were significantly improved with live bacteria. Further histological analysis found that the integrity of the intestinal wall, cell infiltration, and ulcers were also improved. In addition, the tight junction markers of the intestinal tissue were also upregulated.From the above results, we suggest that the human milk bacteria has the ability to allelieve intestinal inflammation, and it can be used in research to explore the molecular effect of probiotics on intestinal inflammation in the future, and it could be potential to be used in clinical application to relieve ulcerative colitis of patients.