Abstract: Objective:To investigate the expression of transit receptor potential ankyrin 1 (TRPA1) and 5hydroxytryptamine (5HT) in the colonic mucosa of patients with slow transit constipation (STC).
Methods: The clinical data of 10 patients with STC and 10 patients with sigmoid cancer who were respectively admitted to the Daping Hospital of the Third Military Medical University from March 2013 to March 2014 and from December 2013 to May 2014 were retrospectively analyzed. Ten and 10 surgical specimens of descending colon from patients with STC and sigmoid cancer (tumor edge measuring in controls>10 cm) were allocated into the STC group and the control group, respectively. The expressions of TRPA1 and 5HT in the colonic mucosa in the control group and in the 2 groups were detected by immunofluorescence and immunochemistry staining, respectively. The expression of TRPA1 in the colonic mucosa was observed by Western blot test.  The measurement data with normal distribution was presented as X±s, and the comparison between groups were analyzed using the t test.
Results:The results of immunofluorescence showed that TRPA1 and 5HT were coexpressed in the colonic mucosa of controls. The results of immunochemistry staining showed that the integrated optical density (IOD) of expressions of TRPA1 and 5HT in the STC group and in the control group were  3 619±1 702, 55 721±28 613 and 9 894±3 325, 12 949±2 200, respectively, showing significant differences between the 2 groups (t=-5.312, 4.713, P<0.05). The results of Western blot test showed that the relative expressions of TRPA1 in the STC group and in the control group were 0.8±0.3 and 1.5±0.5, showing a significant difference between the 2 groups (t=-2.379, P<0.05).
Conclusions:TRPA1 is expressed in the enterochromaffin (EC) cells of colonic mucosa. High expression of 5HT and low expression of TRPA1 in the colonic mucosa are closely related with the pathogenesis of STC.