植物乳植杆菌发酵黄芪对Lewis肺癌荷瘤小鼠的改善作用研究

Study on the Improvement Effect of Fermented Astragalus on Lewis Lung Cancer Bearing Mice

关键词:  发酵黄芪  Lewis肺癌  肠道菌群  代谢

Key words:  fermented Astragalus  lung cancer  gut microbiota  metabolism

摘要:

目的：以 Lewis 肺癌移植瘤小鼠模型为研究对象,体内与体外研究结合探讨发酵黄芪对肺癌的潜在改善作用。方法：将40只C57BL/6小鼠随机分成5组:正常组、模型组、黄芪提取液组、黄芪发酵液组、阳性药物组(顺铂),皮下注射Lewis肺癌细胞（Lewis Lung Carcinoma, LLC）后给药三周。计算小鼠体重、肿瘤体积、肿瘤抑制率与脏器指数,观察肿瘤、肝肾脾组织病理学变化,检测血清免疫细胞因子、肠道菌群与短链脂肪酸的变化情况。采用LLC细胞体外评价黄芪提取液、黄芪发酵液、黄芪提取液组小鼠粪便代谢物、黄芪发酵液组小鼠粪便代谢物对肿瘤细胞增殖率的影响。结果：发酵黄芪具有明显的抗肿瘤效果,肿瘤抑制率为47.2%。发酵黄芪对肺癌小鼠的肝肾脾具有保护作用,可有效防止肝肾脾的组织病理学损伤,增加小鼠脾脏指数、胸腺指数,降低血清IL-1β、TNF-α、IFN-γ、TGF-β、IL-6水平,增加IL-12水平。此外,发酵黄芪调节了肺癌小鼠的肠道菌群,减少Prevotella、Oscillospira、Bacteroides等有害菌或潜在致病菌,增加Lactobacillus、Bifidobacterium、Turicibacter等有益菌,并特异性富集Akkermansia菌。发酵黄芪还可促进肺癌小鼠肠道中乙酸和戊酸等短链脂肪酸的产生。体外研究表明,低中高浓度的发酵黄芪对LLC细胞具有一定的直接抑制作用,细胞增殖率分别为80.58%、72.05%、69.02%,而发酵黄芪组小鼠粪便上清使LLC细胞增殖率降为47.60%,具有更强的LLC细胞抑制能力。结论：发酵黄芪改善小鼠肺癌的能力部分依赖于肠道菌群,且肠道菌群及其代谢的间接抑制作用是发酵黄芪发挥药效的主要途径。发酵黄芪有潜力作为一种肠道微生态调节剂发挥肺癌的防治作用。

Abstract:

OBJECTIVE In this study, Lewis lung cancer transplanted mouse model was used as the research object, and the potential improvement effect of fermented Astragalus on lung cancer was investigated in vivo and in vitro. METHODS A total of 40 C57BL/6 mice were randomized into 5 groups: control, model, unfermented Astragalus, fermented Astragalus, and positive control (cisplatin), which were administered for 3 weeks after subcutaneous injection of lung cancer cells. The body weight, tumor volume, tumor inhibition rate and organ index of mice were calculated, the pathological changes of tumor, liver, kidney and spleen were observed, and the changes of serum immune cytokines, gut microbiota and short-chain fatty acids were detected. The study also evaluated the effects of the unfermented Astragalus, fermented Astragalus, the fecal metabolites of unfermented Astragalus group, and the fecal metabolites of fermented Astragalus group on the proliferation rate of tumor cells using LLC cells in vitro. RESULTS The results showed that fermented Astragalus had obvious anti-cancer effect, with a tumor suppression rate of 47.2%, and it could increase the effective weight of lung cancer mice. Fermented Astragalus also had a protective effect on liver, kidney, and spleen, could prevent histopathological damage of these organs and restore spleen index and thymus index, while lowering the serum levels of IL-1β, TNF-α, IFN-γ, TGF-β, and IL-6 and increasing the level of IL-12. Additionally, fermented Astragalus regulated the gut microbiota of lung cancer mice, reducing harmful bacteria or potential pathogens such as Prevotella, Oscillospira, and Bacteroides, and increasing the beneficial bacteria such as Lactobacillus, Bifidobacterium, Turicibacter, and Akkermansia. Fermented Astragalus also promoted the production of short chain fatty acids such as acetic acid and valeric acid in the intestines of mice with lung cancer. In vitro studies showed that low, medium and high concentration of fermented Astragalus had a certain direct inhibitory effect on LLC cells, with cell proliferation rates of 80.58%, 72.05% and 69.02%, respectively. The fecal metabolites of fermented Astragalus group reduced LLC cell proliferation rate to 47.60%, which showed a stronger LLC cells inhibitory ability. CONCLUSION The ability of fermented Astragalus to improve lung cancer is partly dependent on gut microbiota, and the indirect inhibition of gut microbes metabolism is the main way. Fermented Astragalus has the potential to play a role in the prevention and treatment of lung cancer as an intestinal microecological regulator.