Establishment Of Exogenous Aspergillus Fumigatus Endophthalmitis In Rabbit Eye Model

Objective: Endophthalmitis which caused by the deep or superficial fungus or the conditioned pathogen is a kind of infectious disease inside the eyeball, and has a lower incidence than the bacterial endophthalmitis. It is a kind of severe eye disease leading to blind. Aspergillus fumigatus is a kind of common pathogen having a high pathogenicity. In recent years, with the extensive use of the broad-spectrum antibiotics, the immunosuppressant and the corticosteroid on the clinic, the prevalence of the organ transplantation and the indwelling catheters continuously, and the increasing patients of the AIDS and diabetes mellitus, the fungal endophthalmitis has presented an increasing trend in the proportion of infectious endophthalmitis. About 10 percent of endophthalmitis is caused by Aspergillus fumigatus. Almost all of Aspergillus fumigatus endophthalmitis would lead to blind. The exogenous aspergillus fumigatus endophthalmitis in the model of lagophthalmos that we established is good for the study of pathogenesy as well as pathotoxins, and good for the exploitation of diagnostic technique. It also can estimate the therapeutic effect and provide the experimental basis for the advanced research of fungal endopathalmitis .Method: Chose the aspergillus fumigatus as the infection strain which acts as the common pathogen of Eurotium and has strong virulence. Chose the New Zealand rabbits as fungal endophthalmitis animal model. Twenty-four healthy New Zealand rabbits, weight of 2.0-2.5kg, were randomly divided into eight groups, seven experimental groups and one control group. 0.1mL of the aspergillus fumigatus Albicans susupension concentration as (1.0-1.5)×101,×102,×103,×104,×105,×106,×107CFU.mL-1(colony foming unit,CFU) was respec- tively injected into the right eyes of the experimental groups. 0.1mL normal saline was injected into the right eyes of the control group .There were three model eyes in each group. The progress of disease and clinical feature had been observed by direct ophthalmoscope for 15 days. Tobrex gutta was dropped into the eyes of the experimental rabbits once a day to restrain the germ growth. The extent of bulbar conjunctival injection and edema, the extent of corneal opacity and corneal new vessels, the inflammatory reaction in anterior chamber, iris new vessels, pupillary size and the light via reaction, the varience of vitreous body and retina are the main observation items .The most important is the comparision of the aqueous flare and the vitreous opacity. Vitreous was taken to make fungi culture in the middle of the experiment. All the New Zealand rabbits were executed to make fungi culture of vitreous, blood and main organs. And the cultured fungi were identified by morphology and molecular biology. Histopathologies of the eyes were examined. Repeated experiment was taken in the appropriate concentrations.Result: In my research , no fungi was cultured in blood and main organs of all group of New Zealand rabbits. So we chose the lowest concentration of the aspergillus fumigatus Albicans susupension as the infection standard to obtain the model with typical clinical feature. The aspergillus fumigatus Albicans susupension concentration as (1.0-1.5)×103,×104,×105 CFU.mL-1 is appropriate. In order to guarantee the experiment more credible , repeated experiment was taken in the appropriate concentrations. And typical fungal imfection symptoms of eye were observed in the group of concentration of (1.0-1.5)×104 CFU. mL-1.Conclusion:1. When we choosed the New Zealand rabbits with the weight of 2.0-2.5kg as fungal endophthalmitis animal model, we found that the best concentration of aspergillus fumigatus albicans suspension is (1.0-1.5)x 104 CFU. mL-1 (colony forming unit,CFU). Thus we could obtain perfect fungal infectious symptoms of eye.2. The establishment of exogenous aspergillus fumigatus endophthalmitis in rabbit eye model has high coherence and repeatability. And the model made with different concentration of aspergillus fumigatus albicans suspension could be carried on different research .