Original Article Increased mast cell numbers associated with nerve fiber alterations in the colon from Hischsprung's disease patients

This study is aimed to investigate the pathogenesis of Hischsprung's disease (HSCR) through examina- tion of quantitive and morphological changes of mast cells (MCs) and nerve fibers in different segments of affected colon. Stenotic, transitional, and dilated segments were collected from HSCR patients (n = 62) at the Children's Hospital of Chongqing Medical University from January 2011 to December 2013 (Chongqing, China). Control sam- ples were collected from patients (n = 10) who had died from non-gastrointestinal disease. Toluidine blue stain- ing, immunohistochemistry (mast cell tryptase and S100 antibodies), and compound staining were performed to identify and morphologically characterize MCs and nerve fibers. Sections were examined under light microscopy for the distribution and morphology of MCs and nerve fibers, and the results were evaluated with color image analyz - ing software. MCs were localized in mucosal and submucosal layers, and accumulated around the nerve fibers in HSCR samples. The number of MCs in stenotic HSCR intestine was significantly greater than in dilated intestine or in controls (P < 0.05). Furthermore, MC degranulation and S100-positive fibers were found at a greater degree in the stenotic intestine group (P < 0.05). Finally, the number and the area of S100-positive fibers were positively cor - related with the number of MCs (r = 0.513, P < 0.01; r = 0.474, P < 0.01). The number and morphological changes in MCs and nerve fibers were positively correlated in HSCR samples, indicating that the interaction of MCs with nerve fibers may play an important role in the pathogenesis of HSCR.