Ethanol-induced Gastric Lesion Model Research Articles

Gastroprotective Activity of Sterculia striata A. St. Hil. & Naudin (Malvaceae) in Rodents

The Sterculia striata ethanolic extract (Ss-EtOH) inhibited gastric lesions induced by ethanol, HCl/ethanol, and ischemia/reperfusion, but not those induced by indomethacin, and did not alter the gastric secretion. Ss-EtOH restored the catalase activity and content of nonprotein sulfhydryl groups in the stomach of mice treated with ethanol. The gastroprotection induced by Ss-EtOH in the ethanol-induced gastric lesion model was abolished by N(G)-nitroL-arginine methyl ester (L-NAME) pretreatment, suggesting the involvement of nitric oxide and antioxidant compounds, but not prostaglandins, in this activity. Lupeol obtained from Ss-EtOH promoted gastroprotection as well as the extract at the same dose, and it must therefore contribute to the observed effects.

Effects of hecogenin and its possible mechanism of action on experimental models of gastric ulcer in mice

This study investigates the gastroprotective effects of hecogenin, a steroid saponin isolated from Agave sisalana, on experimental models of gastric ulcer. Male Swiss mice were used in the models of ethanol- and indometacin-induced gastric ulcer. To clarify the hecogenin mechanism of action, the roles of nitric oxide (NO), sulfhydryls (GSH), K+ATP channels and prostaglandins were also investigated, and measurements of lipid peroxidation (TBARS assay) and nitrite levels in the stomach of hecogenin-treated and untreated animals were performed. Furthermore, the effects of hecogenin on myeloperoxidase (MPO) release from human neutrophils were assessed in vitro. Our results showed that hecogenin (3.1, 7.5, 15, 30, 60 and 90mg/kg, p.o.) acutely administered, before ethanol or indomethacin, exhibited a potent gastroprotective effect. Although the pretreatments with L-NAME, an iNOS inhibitor, and capsazepine, a TRPV1 receptor agonist, were not able to reverse the hecogenin effect, this was reversed by glibenclamide, a K+ATP blocker, and indomethacin in the model of ethanol-induced gastric lesions. The hecogenin pretreatment normalized GSH levels and significantly reduced lipid peroxidation and nitrite levels in the stomach, as evaluated by the ethanol-induced gastric lesion model. The drug alone increased COX-2 expression and this effect was further enhanced in the presence of ethanol. It also decreased MPO release and significantly protected the gastric mucosa. In conclusion, we showed that hecogenin presents a significant gastroprotective effect that seems to be mediated by K+ATP channels opening and the COX-2/PG pathway. In addition, its antioxidant and anti-inflammatory properties may play a role in the gastroprotective drug effect.

Mechanisms involved in the gastroprotective activity of esculin on acute gastric lesions in mice

This work describes the gastroprotective actions of esculin (6,7-dihydroxycoumarin-6-o-glucoside) against indomethacin- or ethanol-induced lesions and verifies the role of nitric oxide, ATP-dependent K + channels, prostaglandins, transient receptor potential vanilloid 1 and antioxidant effects in the gastroprotective mechanism of esculin in the ethanol-induced gastric lesion model. The intragastric administration of esculin at doses of 12.5, 25 and 50 mg/kg was able to protect the gastric mucosa against ethanol (0.2 mL/animal p.o.), and esculin at doses of 25 and 50 mg/kg protected against indomethacin-induced lesions (20 mg/kg p.o.). Administration of l-NAME (10 mg/kg i.p.), glibenclamide (10 mg/kg i.p.) or indomethacin (10 mg/kg p.o.), but not capsazepine (5 mg/kg p.o.), was able to reduce the gastroprotection promoted by esculin (25 mg/kg) on the ethanol-induced lesions. Measurements of nitrite, a NO metabolite, were increased in the group that was pretreated with esculin. In terms of antioxidant activity as a gastroprotective mechanism of esculin, the results show that pre-treatment with esculin decreased the amount of GSH, increased SOD activity, did not interfere with the CAT activity and decreased both the MPO activity and the MDA amount. In conclusion, pre-treatment with esculin confers significant gastroprotective and antioxidant activity and leads to a reduction in gastric injury; the mechanisms underlying these effects include stimulation of endogenous prostaglandins, nitric oxide synthesis, opening of K ATP channels and reduction of free radicals or modulation of antioxidant enzyme systems.

Gastroprotective and antisecretory effects of Ailanthus excelsa (Roxb)

Ailanthus excelsa (Roxb), an Egyptian medicinal species highly important for treating numerous diseases, was investigated against experimentally induced gastric ulcer in rodents. We evaluated the gastroprotective effect of four extracts (petroleum ether, diethyl ether, chloroform, and methanol) of A. excelsa bark by using the ethanol-induced gastric lesion model. The pretreatment of animals with methanolic, petroleum ether, and chloroformic extracts (100 mg/kg, oral (p.o.)) from A. excelsa significantly reduced gastric lesion induced by ulcerogenic agent (56, 47, and 70%, respectively) when compared with animals pretreated with vehicle. However, the diethyl ether pretreatment led to the least gastric lesion damage (83%), similar to the standard antiulcer drug, cimetidine, at the same dose (100 mg/kg, p.o.). The lower effective dose of diethyl ether extract, as well as cimetidine, given by intraduodenal route, significantly increased the pH values and reduced the acid output of gastric juice. Sterols, triterpenes,and quassinoids are present in the diethyl ether extract of A. excelsa stem bark, which presented the best gastroprotective action among the studied extracts. Our study confirmed the traditional indications of A. excelsa for the treatment of gastric ulcer.

Gastroprotective activity of Camellia sinensis black tea brew in rats

This study examined the gastroprotective potential of a black tea brew (BTB) of Camellia sinensis Linn. O. Kuntze (Theaceae) using Sri Lankan high grown Dust grade No: 1 tea in a rat ethanol-induced gastric lesion model. Three oral doses of BTB (84, 167, or 501 mg/mL) were used in evaluation of the gastroprotective activity. The results showed a strong dose dependent and significant (p < 0.05) gastroprotective activity (in terms of number, length, and area of hemorrhagic lesions). The gastroprotective activity of BTB was superior to that of the reference drug cimetidine. The high dose of BTB (only dose tested) also offered gastroprotection in rat indomethacin- and serotonin-induced gastric lesion models. Intraperitoneal treatment of BTB and oral treatment of BTB following decaffeination suppressed its gastroprotective potential. However, indomethacin pretreatment did not reduce the gastroprotective potential of BTB in the ethanol-induced gastric lesion model. BTB also increased the gastric mucus content (by Alcian blue test), thickness of the gastric mucus layer (by histopathology), pH of the gastric contents, and possibly the gastric mucosal blood flow, and reduced the gastric acid output of the stomach. BTB also had antihistamine (by wheal test) and antioxidant activity (by the DPPH method) and impaired the gastric transit (by charcoal plug test). It is concluded that BTB of C. sinensis possesses strong oral gastroprotective action, which is mediated via multiple mechanisms. The results also justify the claim made by Sri Lankan traditional practitioners that BTB of C. sinensis has gastroprotective action.

The Role of Capsaicin-Sensitive Afferent Nerves in Protective Effect of Capsaicin against Absolute Ethanol-Induced Gastric Lesions in Rats

The role of capsaicin-sensitive afferent nerves in gastroprotection by capsaicin was investigated in the absolute ethanol-induced gastric lesion model in rats. Capsaicin (0.1 and 0.5 mg/kg, p.o.) inhibited the lesion formation dose-dependently. The protective effect of capsaicin was attenuated by indomethacin-pretreatment and disappeared in capsaicin-sensitive nerve degenerated rats. Capsaicin did not induce the distension of gastric mucosal folds. These results suggested that stimulation of capsaicin-sensitive afferent nerves by capsaicin would enhance the prostaglandin formation, leading to an inhibition of gastric lesions.

The role of capsaicin-sensitive afferent nerves in protective effect of capsaicin against absolute ethanol-induced gastric lesions in rats.

The role of capsaicin-sensitive afferent nerves in gastroprotection by capsaicin was investigated in the absolute ethanol-induced gastric lesion model in rats. Capsaicin (0.1 and 0.5 mg/kg, p.o.) inhibited the lesion formation dose-dependently. The protective effect of capsaicin was attenuated by indomethacin-pretreatment and disappeared in capsaicin-sensitive nerve degenerated rats. Capsaicin did not induce the distension of gastric mucosal folds. These results suggested that stimulation of capsaicin-sensitive afferent nerves by capsaicin would enhance the prostaglandin formation, leading to an inhibition of gastric lesions.

Mucosal Protective Activity of Activated Aluminum Complex

The antacid ES Riopan was acidified ex vivo to pH 2.5 to completely eliminate its buffering capacity and was then tested as a mucosal protective agent. The pH 2.5 acidified antacid solution was named activated aluminum complex. Activated aluminum complex was 8.2 times more potent than its parent antacid in protecting against acidified aspirin-induced gastric lesions in the rat. Activated aluminum complex had a duration of action greater than 10 h in the ethanol-induced gastric lesion model, while ES Riopan was active for 6 h. Activated aluminum complex was able to inhibit both acid- and nonacid-mediated ulcers in the stomach and intestine. Its mucosal protective activity was not blocked by pretreatment with indomethacin. These results demonstrate that the nonbuffering antacid activated aluminum complex exerted a more potent and longer-lasting mucosal protective activity than its parent antacid. The activity was probably due to the presence of a hexaaquoaluminum cation and supports the argument that antacids possess mucosal protective effects independent of their acid-neutralizing capacity.

Effect of epidermal growth factor on non-steroidal anti-inflammatory drug-induced intestinal damage

Epidermal growth factor (EGF, 10 micrograms/kg po, ip, or sc, BID, and 20 micrograms/kg iv) had no protective activity in the indomethacin-induced intestinal lesion model (6 h model). In the ethanol-induced gastric lesion model, EGF (10 micrograms/kg sc) reduced lesions by 52% and reduced gastric acid secretion by 68% (5 micrograms/kg iv). In the 24 h indomethacin-induced intestinal lesion model, pretreatment with EGF (10 micrograms/kg sc, BID; 1 day before and during indomethacin treatment) had no beneficial effects. Therefore, EGF had no protective effects against non-steroidal antiinflammatory drug (NSAID)-induced intestinal lesions at doses that protect against the necrotizing action of ethanol and that inhibit gastric acid secretion in the rat.