Low-intensity pulsed ultrasound combined with ST36 modulate gastric smooth muscle contractile marker expression via RhoA/Rock and MALAT1/miR-449a/DLL1 signaling in diabetic rats.

BACKGROUND: Low-intensity pulsed ultrasound (LIPUS) combined with acupoint can promote gastric motility of diabetic rats. The switch of gastric smooth muscle cell (GSMCs) phenotype was related to the diabetes-induced gastric dysfunction, but the mechanism is not clearly elucidated. This study was aimed at exploring the underlying mechanism of LIPUS stimulation application in diabetic gastroparesis rats. METHODS: In this study, Sprague-Dawley male rats were divided into three groups: control group (CON), diabetic gastroparesis group (DGP), and LIPUS-treated group (LIPUS). LIPUS irradiation was performed bilaterally at ST36 for 20 min per day for 4 weeks. The gastric emptying rate was measured by ultrasound examination. Contraction ability of GSMCs was assessed by muscle strip experiment. The expression of related proteins or mRNAs including α-SMA, SM22α, MHC, RhoA, Rock2, p-MYPT1, MYPT1, p-MLC, MLC, MALAT1, miR-449a, and DLL1 was detected by different methods such as western blotting, RT-qPCR, immunohistochemistry, and immunofluorescence staining, as appropriate. KEY RESULTS: (a) LIPUS stimulation at ST36 could improve the gastric motility dysfunction of diabetic rats. (b) LIPUS increased RhoA, Rock2, p-MYPT1, and p-MLC expression level. (c) MALAT1 and DLL1 contents were decreased, but the level of miR-449a was increased in the LIPUS group. CONCLUSIONS & INFERENCES: LIPUS may affect the contractile marker expression of gastric smooth muscle through the RhoA/Rock and MALAT1/miR-449a/DLL1 pathway to ameliorate DGP.

Low-intensity pulsed ultrasound at ST36 improves the gastric motility by TNF-α/IKKß/NF-κB signaling pathway in diabetic rats.

BACKGROUND AND AIM: Low-intensity pulsed ultrasound (LIPUS) can effectively regulate the central and peripheral nervous system. However, whether LIPUS could act on acupuncture points to modulate the activity of peripheral nervous has rarely been studied. Our study aimed to investigate whether LIPUS at ST36 could improve gastric emptying in diabetic gastroparesis rats. METHODS: Sprague-Dawley male rats were divided into three groups: control group (CON), diabetic gastroparesis group (DM), and diabetic gastroparesis LIPUS treated group (LIPUS). The body weight and blood glucose were recorded every week. Glucose tolerance, gastric emptying rate, and gastric motility were measured before and after treatment. Gastric motility was assessed by ultrasonic examination and Muscle strip experiment. The expression level of c-Kit was assessed by immunohistochemistry staining. Levels of TNF-α, p-NF-κB p-65, NF-κB p-65, and p-IKKß, IKKß were measured by western blot. RESULTS: We reported LIPUS at an intensity of 0.88 W/cm2 exhibited significant differences in functional recovery of gastric delayed emptying in diabetic rats. Through ultrasound gastric motility functional testing and analysis of gastric antral smooth muscle strips indirectly and directly proved the effectiveness of LIPUS for the recovery of gastric delayed emptying. Pathological analysis and western blot indicated that the mechanism by which LIPUS applied to ST36 improved gastric motility may be partially attributed to the inhibition of the TNF-α/IKKß/NF-κB signaling pathway, thereby rescuing the damaged interstitial cells of Cajal network. CONCLUSION: LIPUS at ST36 improved the gastric motility and rescued the damaged networks of interstitial cells of Cajal. LIPUS may have a promising therapeutic potential for diabetic gastroparesis.

Conversion of Ginsenoside Rb1 into Six Types of Highly Bioactive Ginsenoside Rg3 and Its Derivatives by FeCl3 Catalysis.

Ginsenoside Rb1 is an important saponin of ginseng(s); however, Rb1, with 3-O- and 20-O-sugar moieties, has low bioavailability. Here, we report the derivatization of ginsenoside Rb1 to completely generate six types of highly bioactive minor ginsenoside Rg3 and its derivatives by FeCl3 catalysis, the reaction conditions are similar to enzymatic reaction conditions. In FeCl3 catalysis, the only 20-O-sugar-moiety of ginsenoside Rb1 was decomposed into the minor ginsenosides Rk1 and Rg5 with newly produced C-20 ethylene bands; but also hydrolyzed into 20(S)-Rg3 and 20(R)-Rg3; subsequently the C-24(25) ethylene bands of 20(S)-Rg3 and 20(R)-Rg3 were hydrated to 20(S)-25-OH-Rg3 and 20(R)-25-OH-Rg3. After separation of reaction mixture from 34 g ginsenoside-Rb1 by silica-gel-column, the 3.3 g sample I of TLC top-band consisting of Rg5 and Rk1, 8.7 g sample II of TLC middle-band consisting of 20(S)-Rg3 and 20(R)-Rg3, 3.5 g sample III of TLC bottom-band consisting of unknown product-I and -II including 20(S)-25-OH-Rg3, were obtained. The sample III consisting of unknown product-I and -II was purified by crystallization, and identified to 20(S)-25-OH-Rg3 and 20(R)-25-OH-Rg3 by HPLC-Evaporative Light Scattering Detector (ELSD) and NMR. Therefore, six types of minor-ginsenosides Rk1, Rg5, 20(S)-Rg3, 20(R)-Rg3, 20(S)-25-OH-Rg3 and 20(R)-25-OH-Rg3 were successfully prepared from ginsenoside Rb1 by FeCl3 catalysis. FeCl3 has low toxicity and is inexpensive, and the reaction conditions are similar to enzymatic reaction conditions; thus, this method is applicable to the development of ginseng-based drugs.