The Establishment Of Guinea Pig's Model Of Dermatophytosis And The Preliminary Study Of The Pathogenic Process

Dermatophytosis is a common infectious disease caused by fungi.Superficial mycoses are the main pathogens of dermatophytosis in dogs.They attach on canine's epidermis and accessory structure,absorb keratin tissue and breed rapidly,and result in partial hair removal,scaling,erosion and other diseases.Superficial mycoses can be divided into three sorts:Trichophyton(such as Trichophyton mentagrophytes),Epidermophyton(such as Epidermophyton floccosum)and Microsporum(such as Microsporum gypseum).Pityrosporum can also cause dermatophytosis in some cases.Dermatophytosis in dogs can be infected each other within pets or between pets and human beings.Recently,the incidence of dermatophytosis in dogs have been increasing year by year with the abuse of antibiotics and immunosuppressive agents.Dermatophytosis can not only lead to depilation which can cause a serious damage to the beauty of dogs,but also cause itching,affect the dogs' state of life.Therefore,the treatment of dermatophytosis in dogs is very important.At present,dermatophytosis in dogs have different kinds of symptoms,different degrees of severity,and sometimes could appear with other dermatoses caused by bacterium or parasite,which will result in severe hurt,readily reducible and hard cure.However,researches of colledge and institute focus more on the prevention and treatment of dog dermatophytosis.The mechanisms of the characteristic pathology,the mechanisms of host protection against infection,and the reason for intractable dermatophytosis in dogs have not been clarified.Thus,experiments to elucidate these questions regarding dermatophytosis need to use dogs as experimental animals.The suggestion has been made that the model of experimental infection on the back of dogs has a lot of disadvantages:high cost,complicated operation,hard to control animals,and potential danger to the experiment operators.So,this research tried to establish a small animal model to make relevant experiments more convenient,low-priced,safe and controllable.Experiment ? Experimental Dermatophytosis ModelBALB\c mice and guinea pigs were used to establish Trichophyton mentagrophytes dermatophytosis model,clinical observation was performed every two days and scores of skin symptom condition were made.The results showed that Trichophyton mentagrophytes is easier to infect guinea pigs' skin,and the mouse models need to be aided with immune suppression.Both models are safe,convenient and quick,have high controllability and practicability.The guinea pigs are gentler,the skin areas are larger,but the mice have lower prices,and experiment operation requires fewer operators.Through the skin symptom score and pathological sections observation,found that the damage to the skin made by Trichophyton mentagrophytes reached its peak on day 13 to 17 after charge,and after that the disease symptom severity gradually reduced.The lesions in guinea pigs are more obvious and intuitive than mice.Astragalus polysaccharide was used as immune-enhancer which have successfully established guinea pigs dermatophytosis model,showed lower scores of skin symptom condition in day 3 and day 5 after charged,promotion of the immune-enhancer may have value of prevention and treatment in dermatophytosis of dogs.Experiment ? Antifungal susceptibility and clinical efficacy trailsTo evaluate whether the guinea pigs model can be used for in vivo pharmacodynamics experiments,The checkerboard microdilution method was applied to study in vitro interactions of three antifungal drugs(terbinafine,amphotericin B,itraconazole)and combined application of terbinafine and itraconazole,compares the application microplate of three kinds of antifungal drugs alone drug and combination of sterilization effects were observed,some clinical separation strains of antimicrobial susceptibility test results with the clinical effect of correlation analysis.Then established guinea pigs'Trichophyton mentagrophytes dermatophytosis model and executed in vivo pharmacodynamics experiments,the result shows the model is simple,quick and reliable.Experiment III Detection of cytokines by fluorescence quantitative RT-PCRIt is generally believed that the cellular immunity is dominant in the defense of dermatophytosis in dogs,so tried to evaluate the state of cytokines 3,13,26 days after charge to estimate animals' immune status.In accordance with the available primers with sequences designed to detect TNF-?,IL-1,IFN-? and IL-10 mRNA,a method of fluorescence quantitative RT-PCR was established,the result shows that all cytokines were determined in blood by established method,IL-10 and IL-1 increased on day3,TNF-?increased on day 13,IFN-? reached its peak on day 26.