A novel murine model of Fusarium solani keratitis utilizing fluorescent labeled fungi

Fungal keratitis is a common disease that causes blindness. An effective animal model for fungal keratitis is essential for advancing research on this disease. Our objective is to develop a novel mouse model of Fusarium solani keratitis through the inoculation of fluorescent-labeled fungi into the cornea to facilitate the accurate and early identification and screening of fungal infections. F. solani was used as the model fungus in this study. In in vitro experiment, the effects of Calcofluor White (CFW) staining concentration and duration on the fluorescence intensity of F. solani were determined through the mean fluorescence intensity (MFI); the effects of CFW staining on the growth of F. solani were determined by the colony diameter. In in vivo experiment, the F. solani keratitis mice were induced and divided into a CFW-unlabeled and CFW-labeled groups. The positive rate, corneal lesion score and several positive rate determination methods were measured. The MFIs of F. solani in the 30 μg/ml CFW-30 min, 90 μg/ml CFW-10 min and 90 μg/ml CFW-30 min groups were higher than that in the 10 μg/ml CFW-10 min group (P < 0.01). Compared with the 30 μg/ml CFW-30 min group, only the 90 μg/ml CFW-30 min group showed higher MFI (P < 0.05). No significant difference was observed in the colony diameter in the CFW unstained group compared with that in the 10, 30, 90, 270, or 810 μg/ml CFW groups stained for either 10 or 30 min (P > 0.05). No significant differences (P > 0.05) were observed for the positive rate or the corneal lesion scores between the CFW-unlabeled and the CFW-labeled group. On day 1 and 2, the positive rates of the infected corneas in the scraping group were lower than those in the fluorescence microscopy group (P < 0.05). On day 3, these observe methods showed no significant difference (P > 0.05). Thus, these experiments established a novel murine model of F. solani keratitis utilizing fluorescent labeled fungi. This model facilitates the accurate identification and screening of fungal infections during the early stages of fungal keratitis and provides a novel and reliable technology to study the fungal keratitis.