Raman Spectrum Analysis And Mycotoxin Detection In Experimental Keratomycosis

Purpose: To further explore the occurrence and development mechanismof keratomycosis, the expression of biochemical composition and mycotoxins in theinfected cornea were detected in a mouse model of Fusarium solani.Methods: According to the random number table method, BALB/C mice wererandomly divided into two groups: the fungal infection group (experimental group),and the damage control group(control group). On day1,3,5,7,12after inoculation,the appearance of corneal ulcer was observed by slit lamp microscope, the severity ofkeratomycosis was scored. Corneal scraping was obtained from the experimental eyeto perform etiology detection in the corresponding time points. Eyes were excised forraman spectroscopy analyze the changes of biochemical composition. In addition, theexpressions of fusaric acid, fumonisins B1, deoxynivalenol and zearalenone in theinfected cornea were detected by high performance liquid chromatography tandemmass spectrometry (HPLC/MS/MS).Results:1.The infection rate of Fusarium solani was100.0%. The infected corneawas characterized by diffuse inflammation on day1and day2after infection. Thenthe infiltrating cloudy was aggravated. The infected cornea was gray haze on day3after inoculation. The cornea ulcer lesion was expanded and the surface of infectedcornea was dry, slightly uplift on day5, and the neovascularization was present at theperiphery of cornea. The disease began to turn for the better and the area of ulcerlesion was reduced on day7. The disease was stable on day12after inoculation,whereas the cornea lesion was scarring and the neovascularization ingrowth pupil area.2.The analysis result of raman spectroscopy: There was not difference betweennormal cornea and the infected cornea on day1in raman spectrum peak intensity of853cm-1(attribution to tyrosine) and940cm-1(attribution to proline, valine), whereasthe two peak intensity begin to decline on day3after inoculation. Although the twopeak intensity on day5and day7had not much change compared to day3, the twopeak intensity both lower than normal cornea and the infected cornea on day1. The 1244cm-1(attribution to collagen) spectral peak could be found on normal cornea andthe infected cornea on day1, but it can not be found on day3,5,7. The peak intensityof1448cm-1(attribution to phospholipids) had no obvious change between normalcornea and the infected cornea on day1,3,5,7.3. The detection result of mycotoxins:FA, DON and ZEN could not be detected on normal cornea and the infected cornea onday1,3,5,7,12. A little FB1could be detected in the infected cornea tissue on day3and day5, whereas it could not be detected on day1,7,12.Conclusions:1. The relative amount of tyrosine, proline, valine and collagen declinein the infected cornea tissue in the development process of fungal keratitis.2. A littleFB1are detected in the infected cornea tissue, speculate that FB1may play a role inthe development process of fungal keratitis, but it remains to be further studied.