Attachment and invasion of human bronchial epithelium by Aspergillus fumigatas.

我们在具有空气-粘膜界面的器官培养模型中研究了烟曲霉临床分离物与人支气管粘膜的相互作用。利用扫描电镜（SEM）和透射电镜（TEM）观察各时间点（1、6、12、18和24h）烟曲霉分生孢子对支气管黏膜的附着和侵袭以及纤毛上皮的结构变化。电镜显示在12 ~ 24h时明显的上皮损伤，包括细胞间连接分离、纤毛细胞挤压和脱离。扫描电镜（SEM）和透射电镜（TEM）观察到分生孢子在粘膜表面的附着，部分分生孢子在1 ~ 6 h时出现上皮表面的压痕，6 h时分生孢子内化于纤毛细胞内，细胞间分生孢子内化于上皮。秋水仙碱（微管抑制剂）或细胞松弛素D（肌动蛋白丝抑制剂）对支气管器官培养组织进行预处理，可显著抑制呼吸上皮细胞分生孢子的附着和内化。结果表明，烟曲霉侵染人支气管纤毛上皮的机制至少有三种：分生孢子内化于上皮细胞的细胞骨架系统，分生孢子（或菌丝）穿过上皮细胞间间隙，菌丝直接穿过纤毛上皮细胞内间隙，并破坏上皮细胞的细胞质膜。

We have studied interactions of a clinical isolate of Aspergillus fumigatus with human bronchial mucosa in an organ culture model with an air-mucosal interface. A.fumigatus conidia were inoculated on the organ culture tissues, and incubated at 37ﾟC At each timepoint (1,6,12,18 and 24h), attachment and invasion of the bronchial mucosa by A.fumigatus conidia (and hyphae) as well as structural changes of the ciliated epithelium were investigated by scanning and transmission electron microscopy(SEM and TEM). EM demonstrated remarkable epithelial damage including separation of intercellular junction, extrusion and detachment of ciliated cells at 12 to 24h. SEM and TEM revealed attachment of conidia on the surface of the mucosa, some of which were associated with indentation on the epithelial surface at 1 to 6 h, internalization of conidia within the ciliated cells and intercellular conidia in the epithelium at 6 h, and hyphae directly penetrating epithelial cells as well as invading the intercellular space of the epithelium at 18 and 24 h. Pretreatment of the bronchial organ culture tissues with colchicine (microtubule inhibitor) or cytochalasin D (actin filament inhibitor) significantly suppressed the attachment and internalization of conidia in the respiratory epithelial cells.It is suggested that A.fumigatus can invade the human bronchial ciliated epithelium by at least three different mechanisms internalization of conidia within epithelial cells which may be associated with cytoskeleton system of the epithelial cells, penetration of conidia (or hyphae) through the intercellular space of the epithelium, and direct penetration of hyphae through the intracellular space of ciliated epithelium associated with destruction of cytoplasmic membrane of the epithelial cells.