Effects of Saikosaponin D on Apoptosis, Autophagy, and Morphological Structure of Intestinal Cells of Cajal with Functional Dyspepsia.

OBJECTIVE: Functional dyspepsia (FD) is one of the most common gastrointestinal diseases, with a global prevalence of 10%-30%. However, the specific pathogenesis of FD has not yet been determined. As such, the aim of this study was to investigate the effects of saikosaponin D (SSD) administration on the apoptosis, autophagy, and morphological structure of the intestinal cells of Cajal (ICCs) in FD. Methods：A rat model of FD was constructed by stimulating the rat tail with a sponge clamp at one-third of the distal tail length. An autophagy model was constructed for ICCs using glutamate. The apoptosis rate in each group of cells was determined using flow cytometry. The expressions of ghrelin and substance P (SP) were detected using ELISA. RESULTS: The body weight and food intake of male and female rats in the SSD group were consistently higher than those in the model group. The SSD group showed substantial improvement compared with the model group, with no inflammatory cell infiltration and normal gastric mucosal structures. After intervention with SSD, the ultrastructure of the ICCs considerably improved and was clear. Compared with the model group, the expressions of LC3 I/II, ghrelin, and SP proteins in the SSD group were significantly upregulated, and the apoptosis rate was significantly reduced. CONCLUSION: The administration of SSD improved ICC morphology and structure, inhibited excessive autophagy, and improved FD, a gastrointestinal motility disorder, by regulating ghrelin and SP levels.

[Electroacupuncture at "Zusanli"(ST36) promotes gastrointestinal motility possibly by suppres-sing excessive autophagy via AMPK/ULK1 signaling in rats with functional dyspepsia].

OBJECTIVE: To explore the effect of electroacupuncture (EA) at "Zusanli" (ST36) on gastrointestinal motility and expression of autophagy marker LC3 and autophagy signaling pathway molecule AMP-activated protein kinase (AMPK) in rats with functional dyspepsia (FD), so as to explore its mechanisms underlying improvement of FD. METHODS: A total of 40 male SD rats were randomly divided into blank control, model, EA, AMPK inhibitor and EA＋AMPK inhibitor groups, with 8 rats in each group. The FD model was established by tail-clip (30 min/time, twice daily) ＋ single day feeding, and gavage of normal saline (2 mL/time, twice a day) for 2 successive weeks. For rats of EA and EA＋AMPK inhibitor groups, EA (4 Hz, 1.0 mA) was applied to bilateral ST36 for 20 min, once daily for 7 successive days. For rats of the AMPK-inhibitor and EA＋AMPK inhibitor groups, Compound C (20 mg/kg) solution was administered by intraperitoneal injection before every EA administration. The gastric residual rate and small intestinal transit rate were calculated based on the weight of stomach and length of ink propelling and total small intestine, respectively. The expression levels of c-kit, microtubule-associated protein 1 light chain 3, Beclin 1, phosphorylated (p)-AMPK and p-unc-51 like autophagy activating kinase 1(ULK1) in the gastric antrum tissue were detected by using Western blot. RESULTS: Compared with the blank control group, the gastric residual rate and the expression levels of LC3-Ⅱ/LC3Ⅰ， Beclin 1, p-AMPK and p-ULK1 proteins were significantly increased, and the small intestinal transit rate and the expression of c-kit protein obviously decreased in the model group (P<0.01). After EA intervention, modeling-induced increase of gastric residual rate and the expression of LC3-Ⅱ/LC3Ⅰ， Beclin 1, p-AMPK and p-ULK1 proteins, and decrease of small intestinal transit rate and expression of c-kit protein were reversed in the EA, AMPK inhibitor and EA＋AMPK inhibitor groups (P<0.05, P<0.01). The therapeutic effect of EA and EA＋AMPK was significantly superior to that of AMPK inhibitor in down-regulating the expression of LC3Ⅱ/LC3Ⅰ， Beclin 1, p-AMPK and p-ULK1 proteins and in up-regulating the expression of c-kit protein (P<0.05, P<0.01). No significant differences were found among the EA, AMPK inhibitor and EA＋AMPK inhibitor groups in lowering gastric residual rate and elevating the small intestinal transit rate (P>0.05). CONCLUSION: EA at ST36 can promote gastrointestinal motility in FD rats, which is possibly mediated by inhibiting excessive autophagy of interstitial cells of Cajal via down-regulating AMPK/ULK1 signaling.

[Effects of Electroacupuncture on Gastrointestinal Motility and Expressions of VIP and CGRP in Functional Dyspepsia Model Rats].

Objective To observe the effects of electroacupuncture (EA) on vasoactive intesti- nal peptide (VIP) , calcitonin gene-related peptide (CGRP) expression, gastric emptying, and small in- testine advance rate in functional dyspepsia (FD) rats. Methods Totally 48 SD rats were randomly di- vided into three groups, the blank group, the model group, and the EA group, 16 in each group. Except rats in the blank group, FD model was established by tail clamped stimulation plus irregular diet, and ice physiological saline gastrogavage for 14 successive days. After successful modeling EA at Zusanli (ST36) and Taichong (LR3) were performed, once per day for 28 days. Rats were intervened by gastro- gavage at the end of the treatment. Gastric tissue and small intestinal tissue were sampled after anatomy. The rates of gastric emptying and small intestinal transit were determined. Pathological changes of gastric antrum and jejunum tissue were observed by HE staining. mRNA expression levels of VIP and CGRP in gastric antrum and jejunum tissue were determined by Real-time PCR. Results No organic change oc- curred in tissues of the 3 groups. No gastric or intestinal ulcers , inflammatory infiltration, or glandular ep- ithelial lesion occurred in the 3 groups. Compared with the blank group, gastric residual rate obviously in- creased, small intestinal transit rate was lowered, mRNA expression levels of VIP and CGRP in gastric antrum and jejunum tissue were obviously elevated in the model group (P <0. 01, P <0. 05). Compared with the model group, gastric residual rate was obviously reduced, small intestinal transit was obviously elevated, mRNA expression levels of VIP and CGRP in gastric antrum and jejunum tissue were obviously decreased (P <0. 05, P <0. 01). Conclusions EA could significantly decrease mRNA expressions of VIP and CGRP in gastrointestinal tract, accelerate gastric emptying rate and small intestinal transit rate. EA's improving the gastrointestinal motility might be related to decreasing mRNA expressions of VIP and CGRP in gastrointestinal tract, indicating that abnormal secretion braingut peptide might be one of important mechanisms for FD.

[Involvement of Neurotensin-mediated Brain-gut Axis in Electroacupuncture Intervention Induced Improvement of Functional Dyspepsia in Rats].

OBJECTIVE: To observe The effect of electroacupuncture (EA) stimulation of "Zusanli" (ST 36) and "Taichong" (LR 3) on intestinal motor and neurotensin (NT) levels in the plasma, hypothalamus, and gastro-antrum tissues in functional dyspepsia (FD) rats so as to reveal its mechanisms underlying improvement of FD. METHODS: Forty-eight SD rats were randomly divided into control, model and EA groups, with 16 rats in each group. The FD model was established by clamping the rats' tails and alternate day's feeding according to the related references. EA (2 Hz/100 Hz, 2 mA) was applied to unilateral ST 36 and LR 3 for 30 min, once daily for 14 days. Rats of the control group were only restricted. The gastric emptying rate and propulsive rate of the small intestine were detected. The content of NT in the plasma was assayed using ELISA, and the immunoactivity levels of NT in the hypothalamus, gastric antrum mucous membrane and ileum tissues were detected using immunohistochemistry. RESULTS: Compared with the control group, the gastric emptying rate and propulsive rate of the small intestine were considerably lowered in the model group (P < 0.01), and the content and immunoactivity levels of NT in the plasma, hypothalamus, mucous membrane of the gastric antrum and ileum tissues were significantly increased (P < 0.05). After EA intervention, the decreased gastric emptying rate and intestinal propulsive rate, as well as the increased NT content and immunoactivity levels of plasma, hypothalamus, gastric antrum and ileum were reversed (P < 0.05). CONCLUSION: EA intervention can obviously promote gastrointestinal motor in FD rats, which may be related to its function in down-regulating NT levels in the plasma, hypothalamus, gastric antrum and ileum. It suggests an involvement of NT in the brain-gut axis in EA-induced improvement of FD.