Expression of transforming growth factor-β in mast cells in human chronic periapical diseases

This study was undertaken to investigate the distribution of mast cells (MCs) and the expression of transforming growth factor-β (TGF-β) on tryptase positive MCs in different types of human periapical diseases. Periapical tissues of 78 participates were used in this study, including healthy control (n=28), periapical cyst (n=25), and periapical granuloma (n=25). The tissue samples were fixed in 10% formalin for at least 48 h, followed by staining with hematoxylin and eosin (HE) for histopathological examination. Then, they were stained with toluidine blue for MCs and MCs degranulation examination, or stained with double immunofluorescence for identification of tryptase-TGF-β double positive MCs. The results showed that the density of tryptase-TGF-β double positive MCs in periapical lesions was significantly higher than that of healthy control (P<0.01). The number of TGF-β positive MCs in the periapical cyst was potently higher than that in the periapical granuloma (P<0.01). In addition, compared with toluidine blue staining, the number of MCs with double immunofluorescence staining was significantly increased (P<0.01). The TGF-β positive MCs may play an important role in the pathogenesis of human chronic periapical diseases, particularly in the formation of fibrous tissues in periapical cyst. Double immunofluorescence staining is more sensitive than the traditional toluidine blue staining for identifying MCs.