The gastroprotective effect of obestatin on indomethacin-induced acute ulcer is mediated by a vagovagal mechanism

In order to investigate the role of the vagus nerve in the possible gastroprotective effect of obestatin on the indomethacin-induced acute oxidative gastric injury, Sprague-Dawley rats of both sexes were injected subcutaneously with indomethacin (25 mg/kg, 5% NaHCO3) followed by obestatin (10, 30 or 100 μg/kg). In other sets of rats, surgical vagotomy (Vx) or selective degeneration of vagal afferent fibers by perivagal capsaicin was performed before the injections of indomethacin or indomethacin + obestatin (30 μg/kg). Gastric serosal blood flow was measured, and 4 h after ulcer induction gastric tissue samples were taken for histological and biochemical assays. Obestatin reduced the severity of indomethacin-induced acute ulcer via the reversal of reactive hyperemia, by inhibiting ulcer-induced neutrophil infiltration and lipid peroxidation along with the replenishment of glutathione (GSH) stores, whereas Vx abolished the inhibitory effect of obestatin on blood flow and lipid peroxidation, and worsened the severity of ulcer. On the other hand, serosal blood flow was even amplified by the selective denervation of the capsaicin-sensitive vagal afferent fibers, but obestatin-induced reduction in ulcer severity was not altered. In conclusion, the gastroprotective effect of obestatin on indomethacin-induced ulcer appears to involve the activation of the vagovagal pathway.

PHYTOCHEMICAL PROFILE AND GASTROPROTECTIVE ACTIVITY OF EUGENIA MATTOSII FRUITS

ABSTRACT BACKGROUND: Extracts obtained from plants and fruits provide a relatively safe and practical alternative for the conventional medicine of gastrointestinal diseases. The specie Eugenia mattosii, popularly known in Brazil as “cerejinha”, belongs to Myrtaceae family. Species of this family present pharmacological properties, and can be used in the treatment of gastrointestinal disorders. OBJECTIVE: The aim of this study was to determine the phytochemical profile and evaluate the gastroprotective activity of Eugenia mattosii fruits. METHODS: Phytochemical analysis was carried out by thin layer chromatography and gastroprotective assays were performed using two experimental models: acute ulcer model induced by ethanol/HCl and acute ulcer model induced by non-steroidal anti-inflammatory drug (indomethacin). Total lesion area (mm2) and relative lesion area (%) were determined. RESULTS: The results of the phytochemical analysis indicated that the bark and pulp and seeds of E. mattosii present phenolic compounds, terpenes and/or steroids. In gastric ulcer model induced by ethanol was evidenced significant reduction of damaged areas for doses of 50 and 250 mg/ kg of seeds methanol extract, while in the indomethacin-induced ulcer model, all parts of the fruit presented defense capability of the gastric mucosa by reducing lesions at doses of 50, 125 and 250 mg/kg. CONCLUSION: The results demonstrate that the specie E. mattosii has bioactive compounds that provide gastroprotective activity, presenting possible therapeutic potential.

Pantoprazole before Endoscopy in Patients with Gastroduodenal Ulcer Bleeding: Does the duration of Infusion and Ulcer Location Influence the Effects?

The aim of this study was to investigate the effect of preemptive pantoprazole infusion on early endoscopic findings in patients with acute ulcer bleeding. Records of 333 patients admitted with acute ulcer bleeding were analyzed. Ulcer bleeders were given either 80 mg bolus of pantoprazole followed by continuous infusion of 8 mg per hour or saline infusion until endoscopy. In 93 patients saline infusion whereas in 240 patients bolus plus infusion of pantoprazole was administrated with mean (±SD) durations of5.45±12.9hours and6.9±13.2hours, respectively (P=0.29). Actively bleeding ulcers were detected in 46/240 (19.2%) of cases in the pantoprazole group as compared with 23/93 (24.7%) in the saline infusion group (P=0.26). Different durations of pantoprazole infusion (0–4 hours,>4 hours, and>6 hours) had no significant effect on endoscopic and clinical outcome parameters in duodenal ulcer bleeders. Gastric ulcer bleeders on pantoprazole infusion longer than 4 and 6 hours before endoscopy had actively bleeding ulcers in 4.3% and 5% compared to the 19.5% active bleeding rate in the saline group (P=0.02andP=0.04). Preemptive infusion of high-dose pantoprazole longer than 4 hours before endoscopy decreased the ratio of active bleeding only in gastric but not in duodenal ulcer patients.