益生菌对慢性阻塞性肺疾病大鼠肠道菌群和炎症反应的影响

Effects of probiotics on gut microbiota and inflammation in rat models of chronic obstructive pulmonary disease

摘要:

目的 探讨益生菌对慢性阻塞性肺疾病（COPD）大鼠肠道菌群和炎症反应的影响。方法 将30只雄性大鼠随机分为对照组、COPD组和治疗组，每组10只。烟雾刺激和脂多糖（LPS）灌胃复制COPD大鼠模型，并给予治疗组大鼠0.9 CFU/g/（kg·d）益生菌灌胃28 d。观察各组大鼠的一般情况，采用苏木精-伊红染色和Masson染色观察肺组织病理和纤维化改变；免疫荧光双染观察α平滑肌肌动蛋白（α-SMA）的表达；酶联免疫吸附试验（ELISA）检测血清C反应蛋白（CRP）、白细胞介素8（IL-8）和肿瘤坏死因子α（TNF-α）水平；选择性培养基分离培养肠道菌群并计算菌落均值。结果 对照组大鼠饮食活动均正常，毛发顺滑。COPD组大鼠食量减少，呼吸急促，咳嗽频繁，毛发干枯凌乱，但口服益生菌后，治疗组大鼠的症状有一定程度缓解。光镜下可见对照组肺组织形态正常，无炎症浸润和纤维化；COPD组大鼠肺组织存在严重的细支气管管腔狭窄变形、炎症浸润和肺泡纤维化，但口服益生菌后可有效改善。COPD组大鼠肺支气管α-SMA阳性表达较对照组明显增加，但治疗组肺支气管α-SMA阳性表达有所减少。COPD组和治疗组大鼠血清CRP、IL-8和TNF-α水平高于对照组（P <0.05）；而治疗组大鼠血清CRP、IL-8和TNF-α水平低于COPD组（P <0.05）。COPD组和治疗组肠球菌、肠杆菌含量高于对照组（P <0.05）；而治疗组肠球菌、肠杆菌含量低于COPD组（P <0.05）。COPD组乳酸杆菌、双歧杆菌含量低于对照组（P <0.05）；而治疗组乳酸杆菌、双歧杆菌含量高于COPD组（P <0.05）。结论 益生菌可改善COPD大鼠肺损伤和肠道菌群构成，减轻炎症反应。

Abstract:

Objective To investigate the effects of probiotics on gut microbiota and inflammation in the rat models of chronic obstructive pulmonary disease (COPD).Methods Thirty male rats were randomly divided into the control group, the COPD group, and the treatment group, with 10 rats in each group. The COPD rat models were established by cigarette smoke stimulation and intragastric administration of lipopolysaccharide (LPS), and the rats in the treatment group were given probiotics for 28 days at a dose of 0.9 CFU/g/(kg·d). The general conditions of rats in each group were monitored, and the histopathological changes and fibrosis of the lung tissues were observed by hematoxylin and eosin (HE) staining and Masson staining. The expression of α-smooth muscle actin (α-SMA) was measured by immunofluorescence, and the serum levels of C-reactive protein (CRP), interleukin-8 (IL-8), and tumor necrosis factor-α (TNF-α) were quantified by enzyme-linked immunosorbent assay (ELISA). The gut microbiota were cultured in the selective mediums and the average number of colonies was determined.Results The rats in the control group exhibited normal food intake and activities, and their hair was smooth. In contrast, rat models of COPD showed reduced food intake, shortness of breath, frequent cough, and their hair was dry and looked messy. However, these symptoms were relieved to a certain extent in the treatment group. Under the light microscope, the lung tissues of the control group were normal without inflammatory infiltration and fibrosis. The rat models of COPD exhibited severe bronchiolar stenosis and deformation, inflammatory infiltration in the lung tissues, and pulmonary fibrosis, while oral administration of probiotics effectively ameliorated the pathological changes. The expression of α-SMA in the COPD group was higher than that in the control group, while that was decreased in the treatment group (P < 0.05). The serum levels of CRP, IL-8, and TNF-α in the COPD group and the treatment group were higher than those in the control group (P < 0.05), whereas they were decreased in the treatment group compared with the COPD group (P < 0.05). The frequencies of Enterococcus and Enterobacter in the COPD group and the treatment group were higher than those in the control group (P < 0.05), and they were lower in the treatment group compared with the COPD group (P < 0.05). The frequencies of Lactobacillus and Bifidobacterium in the COPD group were lower than those in the control group (P < 0.05), and they were higher in the treatment group compared with the COPD group (P < 0.05).Conclusions Probiotics may ameliorate the lung injury, improve the composition of the gut microbiota, and mitigate the inflammation in rat models of COPD.