- 學位論文
發酵乳酸桿菌經由Nrf2調控降低棕櫚酸誘導脂肪肝模式中HepG2肝細胞之油脂堆積
Alleviative effect of Lactobacillus fermentum on HepG2 liver cells from lipid accumulation in palmitic acid fatty liver induction model via the attenuation on Nrf2
摘要
非酒精性脂肪肝（NAFLD）是一種常見的肝臟疾病，台灣由於飲食及生活習慣的改變，此症狀的患者有逐漸增加的趨勢，部分患者會進展至末期肝病、肝腫瘤，非酒精性脂肪肝是糖尿病發生的重要危險因子，在台灣罹患糖尿病的人口越來越多，其發生因素可能與胰島素抗性、脂質過氧化和不正常的細胞激素(如TNF-α)相關。乳酸菌可增強腸道屏障功能、調節免疫系統，達到保護肝臟效果，但哺乳動物中的腸道乳酸菌可誘導腸內酵素產生ROS，透過Nrf2的途徑，使其產生保護作用，Nrf2執行細胞防禦的功能來抵抗氧化和親電子所造成的壓力並且保護細胞免受於化學性的癌變發生，是調控細胞對抗外來異物和氧化損傷的關鍵轉錄因子，且Nrf2的反應並非通過免疫系統途徑，其對於乳酸菌是否可以透過調控Nrf2產生保護作用改善NAFLD，作用機制並不清楚。本研究將挑選不同種類的蔬果發酵液，進行菌株篩選出耐受性高且能發揮功效之耐鹽乳酸菌，以細胞試驗探討食用乳酸菌調控 Nrf2 減緩非酒精性肝損傷的作用機制。結果顯示，臭豆腐乳汁中篩出之乳酸菌 (NO. 2 及4) 為Lactobacillus fermentum，且與食品工業研究所的BCRC10357之乳酸菌做比較，將其以 MRS 培養後取其上清液作用於棕櫚酸誘發之 HepG2 肝細胞脂肪堆積發現有抑制之效果，同時將此細胞進行西方墨點法分析，發現肝細胞中 Nrf2 蛋白表現量也有增加之趨勢，代表其乳酸菌之代謝物可活化肝細胞之抗氧化能力，以達到抑制脂肪肝之形成，故日後期望能藉由食用蔬果發酵液，減少NAFLD患者發生率。
並列摘要
Non-alcoholic fatty liver disease (NAFLD) is a common liver disease in Taiwan due to changes in diet and lifestyle. There is an increase in disease prevalence and some patients will progress to end-stage liver disease, liver cancer, diabetes population. Moreover, NAFLD is an important risk factor for the development of diabetes. The incidence may be associated with insulin resistance, lipid peroxidation and abnormal cytokines(such as TNF-α) related. Lactic acid bacteria can enhance intestinal barrier function, immune system, hepatoprotection, but mammals’ intestinal lactic acid bacteria could induce intestinal enzyme to produce ROS, through Nrf2 pathway to produce a protective effect. Nrf2 can act for cellular defense function to resist the pressure caused by oxidation and electron affinity and protect cells from cancerous chemical properties. It is the key transcription factor for regulation of foreign bodies and cells against oxidative damage. However, the mechanism of the lactic acid bacteria to improve Nrf2 is whether through the immune system is not clear. In this study, bacteria’s strain of different vegetables and fruits fermentation broths will be carried out to identify lactic acid bacteria. Then, cell experiment will be conducted to observe the mechanism of selected lactic acid bacteria on the regulation of Nrf2 in NAFLD condition. In my results show that I found the two lactic acid bacterials (NO. 2 and 4) are same species, Lactobacillus fermentum, from Chinese stinky tofu sauce and compare with BCRC10357. The culture supernatant of MRS from the lactic acid bacterials (NO. 2, 4 and BCRC10357) inhibited the oil accumulation in HepG2 cells by palmitic acid-induced fatty liver model (Negative group). Furthermore, the western blotting show that the protein expression of Nrf2 was increased compared with the negative group after treated with the supernatant from the lactic acid bacterials (NO. 2, 4 and BCRC10357). The metabolites from the lactic acid bacterials may be inhibit the fatty liver formation via enhancing the antioxidant activity in HepG2 cells. It is expected that the consumption of fermented vegetable-fruit extract can reduce the prevalence of NAFLD patients.
參考文獻
延伸閱讀
- Chen, Y. T. (2018). 馬利乳酸桿菌APS1對高脂飼糧誘導肥胖與非酒精性脂肪肝疾病動物模式之腸道菌相調節與機理研究 [doctoral dissertation, National Taiwan University]. Airiti Library. https://doi.org/10.6342/NTU201801119
- 詹祐忠（2009）。棕櫚酸誘導HepG2肝細胞脂肪堆積與其差異性表現基因〔碩士論文，高雄醫學大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0011-3108200908281900
- 張庭瑜（2018）。棕櫚酸促進陰電性低密度脂蛋白在巨噬細胞中引起 IL-1β 產生透過增加鉀離子流出〔碩士論文，國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342/NTU201801207
- 任治宇（2009）。脂締素透過活化PPARα誘發HO-1/COX-2的表現及對肝細胞鐵過度沉載之保護機制〔碩士論文，臺北醫學大學〕。華藝線上圖書館。https://doi.org/10.6831/TMU.2009.00082
- 顏湘庭（2011）。Lactobacillus is more potent than Bifidobacterium ininducing IFN‐gamma secretion and Th1 lineage differentiation in murine splenocytes〔碩士論文，高雄醫學大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0011-2607201117031600