皮炎外瓶霉黑色素的致病力:基于大蜡螟感染模型的评估

Evaluation of pathogenicity of Exophiala dermatitidis Melanin in Galleria mellonella infection model

目的 采用大蜡螟-皮炎外瓶霉模型评估皮炎外瓶霉黑色素的致病力。方法 采用“共生法”恢复皮炎外瓶霉白化株黑色素的生成,使用皮炎外瓶霉白化株、色素株及色素恢复株构建大蜡螟感染模型,观察最佳感染浓度下各组大蜡螟生存曲线、外观表现及组织病理学变化情况。结果 采用“共生法”可以恢复皮炎外瓶霉白化株黑色素的生成,孢子浓度10^(7)/mL为大蜡螟-皮炎外瓶霉模型的最佳感染浓度。观察终点时,白化株组存活率低于色素株组、色素恢复株组,生存曲线差异具有统计学意义(色素株组与白化株组:χ^(2)=6.11,P=0.013;色素恢复株组与白化株组:χ^(2)=6.37,P=0.010),而色素株组与色素恢复株组生存曲线的差异无统计学意义(χ^(2)=0.01,P=0.940)。组织病理学检查显示,与白化株相比,皮炎外瓶霉色素株及色素恢复株可吸引更多大蜡螟血细胞聚集,形成更大的感染性结节。结论 在蜡螟感染模型中,皮炎外瓶霉白化株表现出比色素株更强的致病力,恢复白化株黑色素的生成,可以逆转白化株致病力。

Objective To evaluate the pathogenicity of Exophiala dermatitidis melanin in Galleria mellonella infection model.Methods Melanin of albino strain of Exophiala dermatitidis was restored by co-culture with E.dermatitidis(mel3).The G.mellonella were infected with albino,melanized strtain,and melanin restored albino strain.Survival rate,macromorphological and histopathological changes of larvae were observed under the optimal infection concentration.Results The melanin production was restored in albino strain of Exophiala dermatitidis,and conidia at a concentration of 1×10^(7)/mL was the optimal infection concentration.At the end of observation,the albino strain displayed lower survival rate compared to both the melanized stain(χ^(2)=6.11,P=0.013)and melanin restored albino strain(χ^(2)=6.37,P=0.010).However,the survival rates did not differ significantly between melanized and melanin restored albino strain(χ^(2)=0.01,P=0.940).Histopathological examination revealed that the melanized strain and melanin restored albino strain attracted aggregation of more Galleria mellonella hemocytes,forming larger infectious nodules in comparison to albino strains.Conclusions In the infection model of Galleria mellonella,the albino strain shows stronger pathogenicity than the melanized strain.Restoration of melanin of albino strain can reverse the pathogenicity.