合併補充益生菌及含魚油之綜合營養劑對BALB/c小鼠腸道免疫與腸-腦軸的影響

Abstract

腸道免疫系統面對大量外來抗原的刺激，其抗原辨識能力與對後續免疫的影響，是免疫調控中相當重要的環節。許多文獻指出益生菌與含魚油營養補充劑均具有免疫調節或抗發炎的功效，因此本研究將探討這兩種飲食因子單獨或合併給予對於腸道免疫的影響。此外，腸道與腦部之間的連結也是近年最新的熱門研究議題，本研究將測定腸道與腦部的血清素含量，初步觀察益生菌與含魚油營養補充劑對血清素與腸-腦軸的可能效應。 非特異性免疫模式使用6週齡BALB/c雌鼠，隨機分為六組，以管餵方式分別給予不同劑量的益生菌與營養補充劑，分別為Ctrl組 (PBS + soybean oil)、Probio益生菌組 (1× probiotics + soybean oil)、Suppl營養補充劑組 (PBS + 1× supplement)、(P+S)-0.5x低劑量組 (0.5× probiotics + 0.5× supplement)、(P+S)-1x中劑量組 (1× probiotics + 1× supplement)及(P+S)-5x高劑量組 (5× probiotics + 5× supplement)，管餵六週後犧牲；以OVA (ovalbumin)致免之特異性免疫模式，組別與第一批相同，惟高劑量組劑量調降為2×為(P+S)-2x，另增加一組未接受OVA的Ctrl-PBS作為對照，餵食期間以腹腔注射OVA致免九週後，犧牲取皮耶氏體 (PP)與腸繫膜淋巴結 (MLN)中免疫細胞進行初代細胞培養，以ELISA測定在LPS及ConA刺激下的細胞激素分泌，利用流式細胞儀分析PP、MLN及脾臟中免疫調控相關細胞次群的比例，另測定腸道與腦部組織中血清素含量。實驗結果指出，益生菌與含魚油營養補充劑能夠促進PP與MLN初代細胞分泌IL-10與TGFβ等免疫調控相關細胞激素，有利維持腸道免疫環境穩定，兩者合併給予具加乘效果；對相關細胞次群例如樹突細胞與調節型T細胞的比例，益生菌與含魚油營養補充劑則無明顯作用。另外，益生菌與含魚油營養補充劑會對腸道與腦部的血清素含量有所影響，兩者合併給予使腸道組織血清素含量增加，而益生菌則有提高腦部血清素含量的潛力，顯示此兩種飲食因子應能在腸道與腦部連結扮演某種角色。 綜合本研究結果，益生菌與含魚油營養補充劑能透過增加免疫調控相關細胞激素的分泌維持腸道免疫環境的穩定，也可能透過改變組織血清素含量而對腸-腦軸有所影響。

Day and night, gut immune system encounters numerous foreign antigens. As a primary site of immune response initiation, it is important for gut immune system to distinguish from self and non-self antigen and affect subsequent immune response properly. The target product of this research includes two popular dietary factor: probiotics and DHA. It has been shown that both of them have certain immunomodulatory and anti-inflammatory effects. Here we give the treatment of probiotics and nutritional supplement containing DHA, separately or combined, to clarify their effect on gut immune system. In addition, we will measure the serotonin content in both intestine and brain to elucidate the link between probiotics or DHA, serotonin and gut-brain axis preliminarily. In non-specific immune animal model, 6 week-old female BALB/c mice were divided into several groups randomly: Ctrl, Probio, Suppl, (P+S)-0.5x, (P+S)-1 xand (P+S)-5x. Animal were sacrificed after 6-week treatment. In OVA-specific immune model, 6 week-old female BALB/c mice were divided into groups as previous. The treat dosage of (P+S)-5 xgroup was adjusted to (P-S)-2x, which received 2X dosage. Mice were immunized by OVA Intraperitoneal injection and sacrificed after 9-week sample treatment. After sacrifice, we analyzed the cytokine production of Peyer’s Patch (PP) and mesenteric lymph node (MLN) primary cell culture and the immunomodulatory cell populations in PP, MLN and splenocyte (SPL). we additionally measured the serotonin content in the tissue homogenate of intestine and brain via ELISA. Although the percentages of regulatory cell population were not affected, combined or separate sample treatment of probiotics and nutrition supplement containing DHA can increase regulatory cytokine production, including IL-10 and TGFβ. This data implies that the product has certain immunoregulatory function. On the other hand, probiotics and nutrition supplement containing DHA also made some impacts on the serotonin content in intestine and brain. However, the precise effects and mechanisms of these two dietary components on gut-brain axis need further elucidations.