Hesperidin Improves Colonic Motility in Loeramide-Induced Constipation Rat Model via 5-Hydroxytryptamine 4R/cAMP Signaling Pathway

Fructus has motivation effect on gastrointestinal tract. Hesperidin is extracts of Fructus, and we attempted to prove its effects on improving the gastrointestinal transmission function and determine the possible mechanisms by a loperamide-induced slow transit constipation (STC) model. Constipation phenotypes were measured in rats with Lop-induced constipation after treatment with hesperidin. The amounts and water content of stool were significantly higher in the hesperidin-treated group than the loperamide-induced model group, whereas food intake was maintained at constant levels. Moreover, intestinal transit rate was increased in the treatment group of hesperidin. Histological alteration was detected by H&E staining, we found that the colon smooth muscle cells and neuron cells of the rats were increased, and the infiltration of inflammatory cells was decreased in the hesperidin-treated group compared with the loperamide-induced model group. 5-Hydroxytryptamine (5-HT) receptor4 fluorescence intensity and intracellular-free calcium ions in colon tissue were increased, and relative protein of cAMP/PKA pathway and p-cAMP response component-binding protein (CREB) pathway were upregulated in the hesperidin-treated group compared with the loperamide-induced model group. Further, SMCs from colon tissue of rats were cultured and identified. We found hesperidin could significantly promote tegaserod-induced increase of 5-HTR4 fluorescence intensity, intracellular calcium ions, relative protein of cAMP/PKA pathway and p-CREB pathway, and cell proliferation and inhibit GR113808-induced decrease of 5-HTR4 fluorescence intensity, 5-HTR4 pathway-related proteins (ADCY3, cAMP, PKA, and p-CREB), intracellular calcium ions, and cell proliferation. The analysis of our data suggested that hesperidin could obviously improve the gastrointestinal transmission function in loperamide-induced STC rat model via increasing the 5-HTR4 and intracellular-free calcium ions to enhance the expression of relative protein of cAMP/PKA pathway and p-CREB pathway. Hesperidin could be used in the treatment of STC, and our data not only provide experimental basis for the treatment of STC in hesperidin but also provides a theoretical reference for clinical treatment.