ABSTRACT
OBJECTIVE: To observe the effect of electroacupuncture (EA) at "Zhongliao" (BL33) and "Xialiao" (BL34) on the 5-hydroxytryptamine (5-HT) signaling system in colon tissue and short-chain fatty acids in feces of rats with slow transit constipation (STC), so as to explore the underlying mechanisms of EA in the treatment of STC. METHODS: A total of 32 SD rats were randomly divided into normal, model, drug control and EA groups, with 8 rats in each group. The STC model was established by intragastric administration of loperamide for 14 days. The EA stimulation (2 Hz/15 Hz) was performed at bilateral BL33 and BL34 for 30 min, once a day for 14 days. The first black stool de-fecation time and fecal water content were detected after treatment. The expressions of 5-hydroxytryptamine 4 receptor (5-HT4R), tryptophan hydroxylase 1 (TPH1) and 5-HT transporter (SERT) in colon tissues were detected by Western blot. The contents of substance P (SP) and vasoactive intestinal peptide (VIP) in serum were detected by ELISA. The contents of 5-HT in colon tissue and short chain fatty acid (SCFA) in feces were detected by mass spectrometry. RESULTS: Compared with the normal group, the fecal water content, the expressions of 5-HT, 5-HT4R, TPH1 and SERT in colon tissue, the content of serum SP were significantly decreased (P<0.05), the first black stool de-fecation time, and the content of serum VIP was significantly increased (P<0.05), the contents of SCFA in feces were significantly decreased except isobutyric acid (P<0.05) in the model group. Compared with the model group, the fecal water content, the expressions of 5-HT, 5-HT4R, TPH1 and SERT in colon tissues, the contents of acetic acid and butyrate in feces were significantly increased (P<0.05) in the EA and drug control groups, the first black stool defecation time was decreased (P<0.05) in the EA and drug control groups, and the content of serum SP was increased and the content of serum VIP was decreased (P<0.05) in the EA group. Compared with the drug control group, the content of serum VIP was significantly decreased (P<0.05), and the expressions of TPH1 and SERT in colon tissue were significantly increased (P<0.05) in the EA group. CONCLUSION: EA at BL33 and BL34 can promote intestinal motility by intervening multiple links of 5-HT signaling system in treating STC.
Subject(s)
Electroacupuncture , Serotonin , Rats , Animals , Serotonin/metabolism , Rats, Sprague-Dawley , Constipation/genetics , Constipation/therapy , Fatty Acids, Volatile , Acupuncture PointsABSTRACT
Ding's herbal enema (DHEP) is a traditional Chinese medicinal therapy that has been used to treat ulcerative colitis (UC) in China. The present study determined the molecular mechanism of the effect of DHEP in UC treatment. C57BL/6J mice were treated with 3.5% (w/v) dextran sulfate sodium (DSS) for 7 days to establish an animal model of colitis. The mice were divided into five groups (n=5): Control, vehicle, DHEP, mesalazine and ß-sitosterol. After oral administration for 7 days, the body weight, disease activity index, histopathology and inflammatory factors were analyzed. The fractions of CD4+Foxp3+ regulatory T (Treg) cells and CD4+IL-17A+ T helper (Th) cells were determined by flow cytometry. Gut microbiota composition was analyzed by next-generation sequencing. The results revealed that DHEP and ß-sitosterol could significantly alleviate the symptoms of DSS-induced UC. Furthermore, the levels of IL-6, cyclooxygenase-2, TNF-α and p65 were reduced after administration of DHEP. Additionally, the data indicated that DHEP could increase the abundance of seven operational taxonomic units (OTUs) and decrease the abundance of 12 OTUs in the gut microbiota. The content of short-chain fatty acids in the colon remodeled the balance of Treg/Th17 cells in DSS-induced UC in mice. The present study preliminarily defined the mechanism of action of DHEP in UC that may be associated with the regulation of the gut microbiota composition, and maintenance of the balance between Treg and Th17 cells. Furthermore, ß-sitosterol exhibited the same effects with DHEP and it could be a possible substitute for DHEP in UC treatment.
ABSTRACT
Cytisine (Cy) is one of the alkaloids that exist naturally in the plant genera Laburnum of the family Fabaceae. With strong bioactivities, Cy is commercialized for smoking cessation for years. In this work, the study of intermolecular interactions between Cy and bovine serum albumin (BSA) was performed by applying fluorescence spectroscopic methods under simulated physiological conditions. The mechanism of fluorescence quenching of BSA by Cy was also studied. Parameters such as bathing temperature, time and solution pH were investigated to optimize the fluorescence quenching. The binding type, binding ratio and binding constant between BSA and Cy were calculated by using the Stem-Volmer equation. Experimental results indicated that Cy can quench the fluorescent emission of BSA statically by forming a 1 : 1 type non-covalent complex and the binding constant is 5.6 x 10(3) L x mol(-1). Synchronous fluorescence spectral research shows Cy may affect the fluorescence emission of Trp residues of BSA. Furthermore, molecular docking is utilized to model the complex and probe the plausible quenching mechanism. It can be noted that the hydrogen bindings and hydrophobic interactions between Cy and BSA change the micro-environment of Trp213, which leads to the fluorescence quenching of BSA.
