ABSTRACT
Objective:To study the regulatory effect of Wumen-Yiji powder on 5-hydroxytryptamine (5-HT) signal transduction system in intestine and hypothalamus of diarrhea irritable bowel syndrome (IBS-D) model rats. Methods:Sixty male SD rats were randomly divided into blank group (10 rats) and diarrhea irritable bowel syndrome group (50 rats). The diarrhea irritable bowel syndrome group formed the diarrhea irritable bowel syndrome model after 2 weeks of senna leaf gavage and restraint stress. They were randomly divided into model group, deshute group (1.5 mg/kg), low, medium and high dose group of Wumen-Yiji San (6, 12, 24 g/kg), with 10 rats in each group. After continuous administration for 2 weeks, the contents of 5-HT in serum, colon and hypothalamus were detected by ELISA; HE staining was used to observe the pathological changes of colon in each group. The protein and mRNA levels of tryptophan hydroxylase 1 (TPH-1), serotonin receptor 3 (5-HT3R), serotonin receptor 4 (5-HT4R), serotonin transporter (SERT) in colon and hypothalamus were detected by Western blot and RT-PCR, respectively. Results:Compared with the model group, the pathological morphology of colon in each treatment group was improved. Compared with the model group, the level of 5-HT in serum and colon significantly decreased ( P<0.05), and the level of 5-HT in hypothalamus of rats in the low, medium, high dose group of Wumen-Yiji San significantly increased ( P<0.05). The expression of TPH-1, 5-HT3R and 5-HT4R protein significantly decreased ( P<0.05), and the expression of SERT protein in the medium, high dose group of Wumen-Yiji San significantly increased ( P<0.05). The expression of TPH-1, 5-HT3R and 5-HT4R protein in hypothalamus increased ( P<0.05), and the expression of SERT protein in the high dose group of Wumen-Yiji San significantly decreased ( P<0.05). The mRNA levels of TPH-1 (4.778 ± 0.604, 3.278 ± 0.668, 1.670 ± 0.361 vs. 6.877 ± 0.148), 5-HT3R (3.807 ± 0.463, 2.697 ± 0.455, 1.132 ± 0.136 vs. 6.322 ± 0.778), 5-HT4R (4.521 ± 0.234, 2.801 ± 0.351, 1.331 ± 0.142 vs. 6.741 ± 0.293) in colon tissue of low, medium and high dose groups of Wumen-Yiji San decreased ( P<0.05). The level of 5-HT4R mRNA (0.616 ± 0.208, 0.726 ± 0.226 vs. 0.521 ± 0.062) increased ( P<0.05), and the level of SERT mRNA (1.563 ± 1.023 vs. 2.612 ± 1.035) in medium, high dose group of Wumen-Yiji San decreased ( P<0.05). Conclusion:The result showed that Wumen-Yiji San could regulate the expression of 5-HT signaling system relating proteins and mRNA in the colon and hypothalamus of IBS-D rats within a certain dose range, so as to improve the symptoms of IBS-D.