Small intestinal mucosa serotonin signal pathway in patients with irritable bowel syndrome

Objective To investigate the changes of small intestinal mucosa serotonin(5-HT)content and the number of enterochromaffin(EC)cells in patients with irritable bowel syndrome(IBS).Methods The three study groups were patients with diarrhea-predominant IBS(IBS-D)(26 cases),constipation-predominant IBS(IBS-C)(24 cases)and healthy controls(26 cases)who underwent endoscope examinations and whose mucosa samples at the descending part of duodenum,proximal end of jejunum and terminal ileum were obtained in the meantime.The high-performance liquid chromatography-electrochemistry(HPLC-ECD)and immunohistochemical methods were used to detect the 5-HT content and enterochromaffin cell(EC cell). Results The small intestinal mucosa 5-HT content in IBS-C patients at the descending part of duodenum,proximal end of jejunum and terminal ileum were 182±90 ng/mg protein,122±54 ng/mg protein,and 61±35 ng/mg protein respectively, which were lower than those in the control group(256±84 ng/mg protein,188±91 ng/mg protein,93±45 ng/mg protein). The 5-HT content at the proximal end of jejunum had a significant difference,compared with that in the normal group(P 0.05).The small intestinal mucosa 5-HT content in IBS-D patients at the above parts did not have significant differences, compared with that in the normal group(P0.05).The number of EC cells in patients with IBS-C and IBS-D did not have significant differences,compared with that in the normal group(P0.05).Conclusion The changes of 5-HT signaling pathway of IBS patients may offer evidence to explain the pathogenesis of IBS,but there exist some differences between IBS-C and IBS-D.