Establishment of a mouse model of atopic dermatitis with overgrowth Malassezia globosa

Abstract

Objective: To establish a mouse model of atopic dermatitis (AD) with overgrowth Malassezia globosa. Methods: Eighteen BALB/c mice were randomly divided into the control group, AD group, NS/M group, AD+NS/M group, Oil/M group and AD+Oil/M group, 3 mice per group. AD model of BALB/c mice were established by topical administration of MC903. Fungi overgrowth experimental models were attempted to establish using suspension of M. globosa with olive oil and normal saline as vehicle, respectively. Clinical manifestations and lesion scoring as well as mycological and histopathological changes of each group were evaluated. Scanning and transmission electron microscopy were also used to observe the changes on hair follicle and hair shaft. Results: Compared with AD group, more severe AD-like lesion, obvious hair loss andincreasedlesion scoring (q=5.95, P<0.01) were observed in AD+Oil/M group. Histopathological results showed that the epidermis thickness of AD+Oil/M group was significantly increased, the dermis was infiltrated by more dense inflammatory cells, and M. globosa colonization lead to damaged hair folliclesand the degeneratedhair shafts. The results of PAS and fungal fluorescence staining showed a mass of M. globosa in the stratum corneum of ear tissues. Overgrowth of M. globosa inside and outside the hair shaft were proved by scanning and transmission electron microscopy. In NS/M group and AD+NS/M group, only a few M. globose yeast cells were observed in the ear tissue using PAS and fungal fluorescence staining, respectively. Conclusion: A mouse model of AD with overgrowth M. globosa could be established treating with suspension of M. globosa using olive oil but not normal saline.

Keywords

• malassezia globosa
• atopic dermatitis
• mouse model
• olive oil