Abstract:
Background Neurotrophins are present in the gastrointestinal tract where they
participate in the survival and growth of enteric neurons, augmentation of enteric
circuits, elevation of colonic myoelectrical activity and also in different aspects of
colitis. Previous studies largely focused on the role of neural and mucosal
neurotrophins in gut inflammation. The expression of neurotrophins in colonic
smooth muscle cells (SMCs) and the interactions of this potential source with colitis
has not been studied in the gut. Methods The expression of NGF, BDNF, NT-3 and
TN-4 in SMCs from longitudinal and circular muscle layers of rat colon from normal
and Dextran sodium sulphate (DSS)-induced colitis rats was measured by ELISA. Key
Results NGF, BNDF, NT-3 and NT-4 are differentially expressed in both longitudinal
and circular SMCs, where the expressions of BNDF and NT-4 proteins were greater
in SMCs from the longitudinal muscle layer than from the circular muscle layer, while
NGF protein expression was greater in circular SMCs and NT-3 expression was equal
in cells from both muscle layers. Induction of colitis with DSS- significantly alters
neurotrophins expression pattern in colonic SMCs. NGF levels upregulated in circular
SMCs. BDNF level was increased in DSS-induced colitis in longitudinal SMCs.
NGF, NT-3 and NT-4 levels were downregulated in longitudinal SMCs of DSSinduced
colitis rats' colon. Conclusions & Inferences Disturbances of neurotrophins
expression in SMCs resulted from colitis might account for the structural and
functional changes in inflammatory bowel disease (IBD) such as loss of enervation
and characteristic hypercontractility of longitudinal muscle in IBD.