Roles of adherence and matrix metalloproteinases in growth patterns of fungal pathogens in cornea.
OBJECTIVE
To investigate the roles of adherence and matrix metalloproteinases (MMPs) in growth patterns of major fungal pathogens in cornea.


METHODS
Ninety-six eyes in 96 rabbits were equally divided into four groups receiving inoculation of fungal conidia of Aspergillus fumigatus, Candida albicans, Fusarium solani, and Penicillium citreo-viride, respectively, to induce fungal keratitis. Corneas in each group were obtained at 2, 8, 16 hr, and 1, 2, 3, 5, and 8 days after inoculation and were subjected to scanning electron microscopy, histopathological examination, and gelatin zymography. Eight saline-inoculated eyes in another eight rabbits served as controls.


RESULTS
All eyes in the fungus-inoculated groups developed fungal keratitis. The binding of conidia to corneal epithelial basement membrane was initiated earlier in the A. fumigatus and C. albicans groups than in the F. solani and P. citreo-viride groups. Destruction of basement membrane began at 1 to 3 days. Histopathologically, infiltration of inflammatory cells was more evident in the A. fumigatus and C. albicans groups than the F. solani and P. citreo-viride groups at 3 days. The hyphae of A. fumigatus and C. albicans traversed the cornea in a plane perpendicular to the stromal lamellae, whereas the hyphae of F. solani and P. citreo-viride lay parallel to the corneal lamellae. MMP-9 and MMP-2 were found in all infected corneas. At 3 days, proteolysis was most active; the level of MMP-9 was higher in the A. fumigatus and C. albicans groups than in the F. solani and P. citreo-viride groups. There were positive correlations among the number of binding conidia, degree of inflammation, and level of MMP-9 (p < 0.05).


CONCLUSIONS
The adherence ability, chemotaxis to neutrophils, and MMP-9 expression level differ in eyes with different fungal pathogens, which may contribute to the different growth patterns of fungi in cornea.
Dong
Xiaoguang
X
Shandong Eye Institute, Qingdao, People's Republic of China.
Shi
Weiyun
W
Zeng
Qingyan
Q
Xie
Lixin
L
D000818:Animals; D001232:Aspergillus fumigatus / Q000502:physiology; D001422:Bacterial Adhesion / Q000502:physiology*; D002176:Candida albicans / Q000502:physiology; D003315:Cornea / Q000201:enzymology / Q000382:microbiology* / Q000648:ultrastructure; D015821:Eye Infections, Fungal / Q000201:enzymology / Q000382:microbiology* / Q000473:pathology; D005260:Female; D005658:Fungi / Q000502:physiology* / Q000648:ultrastructure; D005670:Fusarium / Q000502:physiology; D007634:Keratitis / Q000201:enzymology / Q000382:microbiology* / Q000473:pathology; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D010407:Penicillium / Q000502:physiology; D011817:Rabbits
D020782:Matrix Metalloproteinases