Abstract:

Objective To screen differentially expressed proteins between granuloma- and tinea corporis-derived Trichophyton mentagrophytes strains, and to explore the pathogenesis of T. mentagrophytes in deep and superficial infection. Methods Four T. mentagrophytes isolates from granuloma and 4 isolates from tinea corporis were cultured in agar plates and small steel rings at 27 ℃ and 37 ℃ respectively, followed by morphologic observation. Eight guinea pigs were immunocompromised by glucocorticoids, and superficially and subcutaneously inoculated with the same amount of fungal suspension to develop an animal model of tinea corporis and granuloma, respectively. Two weeks later, the infection of guinea pigs was confirmed by microscopy, fungal culture and histopathology. Proteins were extracted from a highly toxic granuloma-derived T. mentagrophytes strain and a lowly toxic tinea corporis-derived T. mentagrophytes strain, and subjected to two-dimensional electrophoresis, mass spectrometry and identification by using the National Center for Biotechnology Information （NCBI） database. Results The granuloma-derived T. mentagrophytes isolates grew better at 37 ℃ than tinea corporis-derived T. mentagrophytes isolates did, while no significant difference was observed in the morphology of colonies between the two kinds of T. mentagrophytes isolates at 27 ℃. Tinea corporis models were successfully established in guinea pigs with the 8 T. mentagrophytes strains, and the granuloma-derived isolates induced a more intense inflammation than tinea corporis-derived isolates. Granuloma model was constructed only with 3 granuloma-derived strains, which was proved by microscopy, fungal culture and histopathology. A total of 463 ± 20 and 398 ± 17 protein spots were detected, with 62 and 21 upregulated proteins, from granuloma-derived and tinea corporis-derived T. mentagrophytes strains, respectively. Bioinformatics analysis revealed the following meaningful proteins from differentially expressed proteins in granuloma-derived T. mentagrophytes strains, including enolase, heat shock protein, serine/threonine protease, cellular signal transduction proteins, energy metabolism-related proteins, cytoskeleton proteins and some hypothetical proteins. Conclusions The granuloma-derived T. mentagrophytes strains are more heat-resistant with a higher potency to cause infection compared with tinea corporis-derived T. mentagrophytes strains. Differences exist in the expression of proteins between granuloma- and tinea corporis-derived T. mentagrophytes strains.