Fukada Kazutake, Fujikura Daisuke, Nakayama Yosuke, Kondoh Masatoshi, Shimada Takashi, Miyazaki Tadaaki
Division of Bioresources, Research Center for Zoonosis Control, Hokkaido University, Sapporo, 001-0020 Japan ; Central Research Laboratories, Nichinichi Pharmaceutical Corporation Ltd., 239-1 Tominaga, Iga, Mie, 518-1417 Japan.
Springerplus. 2013 Jun 20;2(1):269. doi: 10.1186/2193-1801-2-269. Print 2013 Dec.
Infection with influenza A virus, one of the most common life-threatening viruses, causes the accumulation of inflammatory cells in the lung, which is directly correlated with influenza-associated morbidity and mortality. In this study, we investigated the potential of lysozyme-treated Enterococcus faecalis FK-23 (LFK) to prevent influenza in influenza virus-infected mice. C57BL/6N mice were orally administered LFK and intranasally infected with influenza virus A/Puerto Rico/8/34 (H1N1) at lethal doses. After infection with influenza A virus, the survival rate of the LFK-administered mice was significantly higher than that of saline-administered mice. Staining of lung sections with hematoxylin-eosin, and cell counts of lung and bronchoalveolar lavage fluid showed that oral administration of LFK suppressed the excessive infiltration of leukocytes into the lung after viral infection. Extravasation assay revealed that the arrest was mediated by modulation of pulmonary alveolar-capillary permeability. Expression levels of genes involved in matrix degradation, which are correlated with vascular permeability, were downregulated in LFK-administered mice. These findings suggest that stabilizing the integrity of the alveolar-capillary barrier by the administration of LFK improves survival rate.
甲型流感病毒是最常见的危及生命的病毒之一，其感染会导致肺部炎症细胞积聚，这与流感相关的发病率和死亡率直接相关。在本研究中，我们调查了溶菌酶处理的粪肠球菌FK-23（LFK）预防流感病毒感染小鼠流感的潜力。给C57BL/6N小鼠口服LFK，并经鼻内感染致死剂量的甲型流感病毒A/波多黎各/8/34（H1N1）。感染甲型流感病毒后，给予LFK的小鼠存活率显著高于给予生理盐水的小鼠。用苏木精-伊红对肺切片进行染色，并对肺和支气管肺泡灌洗液进行细胞计数，结果表明口服LFK可抑制病毒感染后白细胞向肺内的过度浸润。渗出试验表明，这种阻止作用是由肺泡-毛细血管通透性的调节介导的。在给予LFK的小鼠中，与血管通透性相关的基质降解相关基因的表达水平下调。这些发现表明，通过给予LFK稳定肺泡-毛细血管屏障的完整性可提高存活率。
