Tryptase and TIM-1 double-positive mast cells in different stages of human chronic periodontitis

Mast cells (MCs) play a critical role in the pathogenesis of allergic reactions and inflammatory conditions through the release of inflammatory mediators. T cell immunoglobulin mucin domain (TIM-1) has been reported to express in MCs. The aim of the present study was to examine the expression and analyze the quantification of TIM-1 on tryptase-positive MCs in different stages of human chronic periodontitis using double-immunofluorescence staining.

Individuals who participated in this study were divided into three groups: healthy control gingivae (n = 27), chronic slight periodontitis (n = 34), and chronic severe periodontitis (n = 31). Their gingival specimens were taken and fixed in 10% buffered formalin, stained with hematoxylin and eosin (HE) for histopathology, and stained with double-immunofluorescence (DIF) for identification of tryptase-TIM-1 double-positive MCs in gingival tissues.

Compared with healthy controls, the densities (cells/mm²) of tryptase-TIM-1 double-positive MCs were significantly increased in both the chronic slight periodontitis (P < 0.05) and severe periodontitis groups (P < 0.01). However, compared with the chronic slight periodontitis group, both the score of gingival tissue inflammation and the density of tryptase-TIM-1 double-positive MCs in gingival tissue were significantly increased in the severe periodontitis groups (P < 0.05). Conclusion: By incorporating HE with double-immunofluorescence staining in human chronic periodontitis, the significantly increased number of tryptase-TIM-1 double-positive MCs had the similar tendency as the severity of periodontitis inflammation. Based on our results, we suggest that tryptase-TIM-1 double-positive MCs may play an important role in human chronic periodontitis.