Invasion and survival of Fusarium solani in the dexamethasone-treated cornea of rabbits.
Invasion and survival of Fusarium solani in the dexamethasone-treated cornea of rabbits.
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DOI：
10.1080/02681219180000631
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发表时间：
1991-11
期刊：
影响因子：
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通讯作者：
H. Kiryu;S. Yoshida;Y. Suenaga;M. Asahi
中科院分区：
文献类型：
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作者：
H. Kiryu;S. Yoshida;Y. Suenaga;M. Asahi
通过电镜观察和体外实验，对兔实验性茄枯菌角膜炎进行研究，研究真菌侵入角膜基质的方式，外用地塞米松（DXM）治疗下茄枯菌与炎症细胞的相互作用，以及真菌在dexamethasone （DXM）治疗后角膜中的生存机制。电子显微镜显示，当真菌侵入角膜基质时，菌丝周围发生胶原原纤维的消化，那里经常发现无定形物质。在未处理ddxm的角膜中，真菌菌丝被中性粒细胞假足包裹，在感染第3天菌丝被破坏，到第7天大部分菌丝消失。然而，在ddxm处理的角膜中，中性粒细胞不能摄取和破坏菌丝。在兔外周血中性粒细胞定性硝基蓝四氮唑（NBT）还原实验中，ddxm显著抑制了NBT的还原率和真菌微孢子的粘附率。在ddxm治疗的角膜病变中，真菌过氧化物酶体的数量和大小都有相当大的增加。此外，在中性粒细胞的包围下，菌丝表现为双重或三重细胞壁，有时也表现为菌丝中的菌丝结构。在体外用抑菌浓度的H2O2处理时，也观察到类似的菌丝中菌丝结构。我们认为，这种特殊的结构是一种保护装置，当受到中性粒细胞攻击时，在ddxm治疗的角膜中产生梭氏梭氏菌的生存。
Electron microscopic observations, as well as in vitro experiments, on experimental Fusarium solani keratitis of rabbits were performed to study the mode of fungal invasion into the corneal stroma, the interactions between F. solani and inflammatory cells under the influence of topical dexamethasone (DXM) treatment, and the survival mechanism of the fungi in the DXM-treated cornea. Electron microscopy showed that, while the fungus invaded into the corneal stroma, digestion of collagen fibrils occurred around the hyphae, where amorphous material was often noted. In DXM-nontreated cornea, the fungal hyphae were entrapped by pseudopodia of the neutrophils and destruction of the hyphae was noted on day 3 of infection, most hyphae having disappeared by day 7. In the DXM-treated cornea, however, neutrophils could not ingest and destroy the hyphae. In qualitative nitroblue tetrazolium (NBT)-reduction tests using rabbit peripheral blood neutrophils, DXM significantly suppressed the rate of NBT-reduction and the rate of adherence to the fungal microconidia. In the DXM-treated corneal lesions, a considerable increase in both number and size of fungal peroxisomes was noted. Furthermore, the hyphae, surrounded by neutrophils, showed double or triple cell wall formation or sometimes a hypha-in-hypha structure. Similar hypha-in-hypha structures were also observed when the organisms were treated in vitro with a fungistatic concentration of H2O2. We suggest that this special structure is a protective device produced for the survival of F. solani when subject to neutrophil attack in the DXM-treated cornea.