| Objective: Onychomycosis is a common disease in dermatology.Now we have known about its pathogeny exactly.However, the therapy is difficult.Usually we treat it by the oral drugs such as fluconazole, itraconazole, terbinafine and so on. But the drugs are expensive, the clinic doctor must be concious of their antifungal spectrum. Recently we are accustomed to adopt the extrisic antifungal sensitivity test to screen the drugs.Through investigating minimal inhibitory concentration(MIC) of the drugs in the culture medium,we distinguish that the drugs should be or not be effective to certain fungus. Though this method is easy ,its result ranges from one to another under different conditions.Either it can't reflect the drug's function in the intracorporal environment. Considering these shortcomings,our experiment's objective is to look for a new way to investigate the drug's antifungal effect in the nail. In the first step,we must establish an extrinsic onychomycosis model.In the experiment,we destroyed the normal nails with 2.5% NAOH,then put them into 4 testtubes which contained the potato dextrose(PD) fluid medium.In the same time,4 typical pathogenic fungi were selected to be cultured in the tubes.These fungi included trichophyton rubrum, trichophyton gypseum,candida albicans and candida krusei.After 30 day's culture,the nails were cut into pathological sections and stained through Periodic acid and Schiff's(PAS) staining method.Finally,we found hyphas and spores in each nails by the microscopic examination.It proved that the extrinsic onychomycosis model was established successfully.In the second step,we attempted to testify fluconazole's antifungal ability in the nails by the extrinsic onychomycosis model.Firstly, fluconazole was dissolved into solution with varied concentration.Secondly The isolated nails were immerged into the drug solution.Thirdly,four kinds of fungi(same as the above) were cultured with these nails.In the end,we considered fluconazole which was in different concentration solution was or not sensitive to the fungi by the negative or positive result of the nails' section.The fluconazole's antifungal effect inside and outside the nail was compared by the statistical method.Materials and methods:To establish an extrinsic onychomycosis model,we collected the nails of normal people and washed them repeatedly in the distilled water.Then the nails were immerged into 2.5%NAOH for3-6 hours in order to destroy their compact structures.After that ,the NAOH component was removed by the distilled water because the fungi couldn't live with it.In the sequence,the nails were placed into PD fluid medium in the 4 tubes and sterilized in high temperature and pressure conditions.4 kinds of fungi were selected to be cultured in the tube,which included trichophyton rubrum, trichophyton gypseum,candida albicans and candida krusei.Before the culturing,they were made into 1-5×107cfu/ml suspension. After 30 day's culture with fungi in the incubator,the nails were cut into sections and stained by the PAS method.The sections showed that all the fungi had invaded into the nails.To contrast the fluconazole's antifungal activity in the nails with its activity out of the nails,we dissolved the drug powder in the 10% dimethylsulfoxide(DMSO) because the DMSO could pass through the stratum corneum of the nail easily. The drug solution were divided into 4 groups,which were ready to 4 kinds of fungi and there were 3 tubes in each group.According the MIC of fluconazole which had been meatured in the sensitivity test invitro,the concentraton of drug solution in 3 tubes ranged from MIC,10×MIC to 100×MIC.Then 3 pieces of destroyed nails were put into each tube for 20 days. 20 days later,the nails were removed from the drug solution to another tubecontaining PD fluid medium .The fungi suspension of trichophyton rubrum, trichophyton gypseum,candida albicans and candida kruseiwere planted into 4 groups of tubes individually for 30 days' culture.As before,the nails were made int...
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