Su Xiaoling, Liao Daoyong, Li Chao, Chen Li, Wang Jingyun, Gan Tian, Luo Haodang, Wu Ning, He Jun
Department of Laboratory Medicine, Hengyang First People's Hospital, Hengyang 421001, China.
Clinical Laboratory, Hengyang First People's Hospital, Hengyang 421001, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2024 Dec 20;44(12):2300-2307. doi: 10.12122/j.issn.1673-4254.2024.12.05.
To investigate the protective effect of the probiotic bacterium K12 (K12) against (Mp) infection in mice.
Forty male BALB/c mice were randomized into normal control group, K12 treatment group, Mp infection group, and K12 pretreatment prior to Mp infection group. The probiotic K12 was administered daily by gavage for 14 days before Mp infection induced by intranasal instillation of Mp. Three days after Mp infection, the mice were euthanized for analysis of bronchoalveolar lavage fluid (BALF) cell counts and serum levels of secretory immunoglobulin A (sIgA), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). RT-qPCR was performed to detect the P1 and community-acquired respiratory distress syndrome ( CARDS ) toxin of Mp in the lung tissues and the mRNA expressions of TNF-α, IL-6, chemokine 1 (CXCL1), matrix metalloproteinase 9 (MMP9), mucin 5ac (MUC5ac), collagen 3a1 (Col3a1), Toll-like receptor 2 (TLR2) and TLR4; the protein expressions of TLR2 and TLR4 in the lung tissue were detected using Western blotting. Pathological changes in the lung tissue and airway remodeling were examined with HE staining and AB/PAS staining.
Compared with the Mp-infected mice with PBS treatment, the infected mice with K12 treatment showed significantly lowered mRNA levels of P1 and CARDS in the lung tissue and reduced white blood cell counts in the BALF (<0.05). In spite of the absence of significant differences in serum levels of inflammatory factors between the two groups, the mRNA expressions of TNF‑α, IL-6, CXCL1, MMP9, MUC5ac and COL3A1 and the mRNA and protein levels of TLR2 and TLR4 in the lung tissues were significantly lower in K12-treated mice, in which AB/PAS staining showed obviously decreased mucus secretion.
K12 pretreatment can effectively reduce pulmonary inflammatory responses, improve airway remodeling and alleviate lung injury in Mp-infected mice.
研究益生菌K12对小鼠肺炎支原体（Mp）感染的保护作用。
将40只雄性BALB/c小鼠随机分为正常对照组、K12治疗组、Mp感染组和Mp感染前K12预处理组。在通过滴鼻法诱导Mp感染前，每天经口灌胃给予益生菌K12，持续14天。Mp感染3天后，对小鼠实施安乐死，以分析支气管肺泡灌洗液（BALF）细胞计数以及血清中分泌型免疫球蛋白A（sIgA）、肿瘤坏死因子-α（TNF-α）和白细胞介素-6（IL-6）的水平。进行逆转录定量聚合酶链反应（RT-qPCR）以检测肺组织中Mp的P1和社区获得性呼吸窘迫综合征（CARDS）毒素以及TNF-α、IL-6、趋化因子1（CXCL1）、基质金属蛋白酶9（MMP9）、黏蛋白5ac（MUC5ac）、胶原蛋白3a1（Col3a1）、Toll样受体2（TLR2）和TLR4的mRNA表达；使用蛋白质印迹法检测肺组织中TLR2和TLR4的蛋白表达。采用苏木精-伊红（HE）染色和AB/PAS染色检查肺组织的病理变化和气道重塑情况。
与用磷酸盐缓冲液（PBS）处理的Mp感染小鼠相比，接受K12治疗的感染小鼠肺组织中P1和CARDS的mRNA水平显著降低，BALF中的白细胞计数减少（<0.05）。尽管两组之间炎症因子的血清水平无显著差异，但接受K12治疗的小鼠肺组织中TNF-α、IL-6、CXCL1、MMP9、MUC5ac和COL3A1的mRNA表达以及TLR2和TLR4的mRNA和蛋白水平显著较低，其中AB/PAS染色显示黏液分泌明显减少。
K12预处理可有效减轻Mp感染小鼠的肺部炎症反应，改善气道重塑并减轻肺损伤。
