含Lactobacillus casei strain Shirota發酵乳製品對BALB/c鼠之免疫調節作用

Abstract

乳酸菌之生理功效包括促進腸道健康、緩和乳糖不耐症、降低血清膽固醇含量及免疫調節等作用。本研究之目的在評估以Lactobacillus casei strain Shirota (LcS)為菌種之發酵乳製品，對於BALB/c小鼠免疫調節功能之影響。依據衛生署健康食品之免疫功能評估方法，以動物模式評估非特異性與特異性免疫反應。本實驗以市售顆粒狀飼料為基本飼料組成，以管餵方式額外補充試驗之發酵乳製品，將實驗小鼠60隻依體重隨機分為空白組(蒸餾水)、控制組(未發酵之相同成分培養基)以及三個處理組(分別為低、中、高劑量，相當於成人劑量為50、100、300 mL/60 kg/day)。在非特異性免疫功能評估方面，以三個處理組與空白組比較結果顯示，在吞噬細胞活性及自然殺手細胞活性之分析皆有顯著提升的效果，相較於控制組，高劑量組有顯著提升吞噬細胞活性，且中、高劑量組有顯著提升自然殺手細胞活性之效果，顯示有提升先天性免疫之效果；在脾臟細胞增生能力方面，以脂多醣(lipopolysaccharide, LPS)刺激下，低劑量組顯著高於空白組，具有刺激B細胞活化之功能；在細胞激素分泌量方面，三個處理組與控制組比較，有提升介白素-2 (interleukin-2, IL-2)、干擾素-γ (interferon-γ, IFN-γ)、IL-4但降低IL-5之效果，其中以高劑量組效果較顯著；在血清非特異性抗體方面，高劑量組在免疫球蛋白G (immunoglobulin G, IgG)及IgM有顯著的提升作用，有促進B細胞活化之效果。特異性免疫功能評估結果顯示，在吞噬細胞活性方面，三個處理組相較於空白組與控制組，均有顯著的提升，而自然殺手細胞活性方面，中、高劑量組相較於空白組與控制組，均有顯著的提升，顯示有提升先天性免疫之效果；脾臟細胞增生能力方面，在OVA (ovalbumin)刺激下，空白組與低劑量有顯著提升；在細胞激素分泌量方面，三個處理組與控制組相比，有顯著提升IL-4且降低IL-5分泌量之效果；在血清非特異性抗體方面，低、中劑量組在IgA及IgM皆有顯著高於控制組的情形，具有促進B細胞活化之效果；血清中OVA特異性方面，高劑量組之IgG1分泌量顯著低於空白組，且低、中劑量組之IgG2a分泌量相較於空白組有顯著提升效果，顯示具有調節Th1/Th2平衡之效果。

The physiological functions of lactic acid bacteria (LAB) include improving intestinal tract health, reducing symptoms of lactose intolerance, decreasing blood serum cholesterol and enhancing the immune system. The aim of this study is to evaluate the immunomodulatory effects of fermented milk with Lactobacillus casei strain Shirota (LcS) in BALB/c mice. The animal models were used to evaluate for non-specific and specific immune responses on the basis of the regulations of “Health-Promoting Food” of FDA, Taiwan. In this experiment, 60 BALB/c mice were divided into 5 groups according to their weight, and gave them commercial chow diet with supplementary trial fermented milk by oral administration of blank (distilled water), control (the same component medium without fermented), low, medium and high dosages (equivalent to 50, 100, 300 mL/60 kg/day for adult). The results of the non-specific immune study showed that three experimental groups significantly increased phagocytosis and natural killer (NK) cells activities compared with blank group. High dosage group significantly enhanced phagocytosis activities, as well as medium and high dosage groups enhanced NK cells activities compared with control group. These results showed that improved innate immunity. Splenocyte proliferation significantly increased in low dosage group compared with blank group by lipopolysaccharide (LPS) stimulating, and stimulated B cells to activate. The cytokines secretions significantly decreased in interleukin-2 (IL-2), but increased in interferon-γ (IFN-γ), IL-4 and IL-5 at all three dosages compared with blank group. But compared with control group, we observed that three dosages significantly promoted entire secretions of IL-2, IFN-γ, IL-4 and IL-5, and the high dosage group significantly increased immunoglobulin G (IgG) and IgM, and that activated B cells. The results of the specific immune study showed that phagocytosis activity was significantly enhanced compared with blank and control groups. The medium and high groups significantly enhanced NK cells activities compared with blank and control groups, showed that they promoted immunity. Splenocyte proliferation significantly decreased in high dosage compared with blank and control groups by phytohemagglutinin (PHA) stimulating. The cytokines secretions significantly increased in IL-2 and IL-12, and decreased in IL-5 at all three dosages compared with blank group. The low and medium dosage groups significantly increased in serum IgA and IgM compared with control group to promote B cells to activate. The OVA specific antibodies significantly decreased in IgG1 at high dosage group, and significantly increased in IgG2a at low and medium dosage groups to regulate Th1/Th2 balance.