Rabbit gastric ulcer models: comparison and evaluation of acetic acid-induced ulcer and mucosectomy-induced ulcer

Antiulcerative potential of sweet potato (Ipomoea batatas) against aspirin-induced gastric ulcers in a rabbit model

OBJECTIVES

Sweet potato (Ipomoea batatas) is accredited as a functional food because of its nutraceutical compounds. These dietary components may help heal lesions and ulcer scars in the stomach. This research was designed to examine the antioxidant and antiulcerative potential of sweet potato (red skin, white flesh) against aspirin-induced gastric ulcers in a rabbit model.

METHODS

Sweet potato samples were analyzed for in vitro analysis, such as 2,2-diphenyl-1-picrylhydrazyl assay, total phenolic content, and total flavonoid content. In a bioefficacy study, rabbits were divided into five groups (n = 6) in which G0 received the standard diet only, G1 150 mg/kg aspirin, G2 20 mg/kg omeprazole, G3 1000 mg/kg aqueous extract of sweet potato, and G4 1000 mg/kg ethanolic extract of sweet potato. After completion of the trial, the animals were decapitated and examined for antiulcer parameters, serum analysis, and hematologic parameters.

RESULTS

The mean values for 2,2-diphenyl-1-picrylhydrazyl, total phenolic content, and total flavonoid content were 57%, 927 mg gallic acid equivalent/100 g, and 1901 µg quercetin equivalent/g, respectively. The values for gastric volume, acid output, ulcer scores and index, total oxidant status, white blood cell count, and lymphocyte count were increased significantly (P < 0.05) for the positive control group compared with G2, G3, and G4. Gastric pH and body weight at the end of the experiment were significantly reduced for the positive control group (P < 0.05) compared with G2, G3, and G4. Histology test results of gastric tissues in G1 depicted severe epithelial damage compared with G2, G3, and G4.

CONCLUSIONS

The results for the antiulcer parameters ascertained the antiulcer activity of sweet potato in aspirin-induced gastric ulcer models.

Effect of p-cymene and rosmarinic acid on gastric ulcer healing - Involvement of multiple endogenous curative mechanisms

BACKGROUND

p-Cymene and rosmarinic acid are secondary metabolites found in several medicinal plants and spices. Previous studies have demonstrated their anti-inflammatory, antioxidant, and cytoprotective effects.

PURPOSE

To evaluate their gastroduodenal antiulcer activity, gastric healing and toxicity in experimental models.

METHODS

Preventive antiulcer effects were assessed using oral pre-treatment on HCl/ethanol-induced gastric lesions and cysteamine-induced duodenal lesions models. Gastric healing, the underlining mechanisms and toxicity after repeated doses were carried out using the acetic acid-induced gastric ulcer rat model and oral treatment for 14 days.

RESULTS

In the HCl/ethanol-induced gastric ulcer and cysteamine-induced duodenal injury, p-cymene and rosmarinic acid (50-200 mg/kg) decreased significantly the ulcer area, and so prevented lesions formation. In the acetic acid-induced ulcer model, both compounds (200 mg/kg) markedly reduced the ulcerative injury. These effects were related to an increase in the levels of reduced glutathione (GSH) and interleukin (IL)-10, and due to a decrease in malondialdehyde (MDA), IL-1β, tumor necrosis factor (TNF)-α, total and mitochondrial reactive oxygen species (ROS) levels. Downregulation of factor nuclear kappa B (NFκB) and enhanced expression of suppressor of cytokine signaling (SOCS)3 were also demonstrated. Furthermore, positive vascular endothelial growth factor (VEGF), metalloproteinase (MMP)-2, and cyclooxygenase (COX-2)-stained cells were increased in treated groups. Treatment also upregulated the platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), transforming growth factor (TGF)-β and epidermal growth factor receptor (EGFR) in gastric tissues. In isolated gastric epithelial cells this healing effect seems to be linked to a modulation of apoptosis, proliferation, survival and protein phosphorylation, such as the extracellular signal-regulated kinases (ERK)1/2 and p38 mitogen-activated protein kinase (MAPK). Oral toxicity investigation for 14 days revealed no alterations in heart, liver, spleen, and kidneys weight nor the biochemical and hematological assessed parameters. p-Cymene and rosmarinic acid also protected animals from body weight loss maintaining feed and water intake.

CONCLUSIONS

Data altogether suggest low toxicity, antiulcer and gastric healing activities of p-cymene and rosmarinic acid. Antioxidant and immunomodulatory properties seem to be involved in the curative effect as well as the induction of different factors linked to tissue repair.

Protective effect of the solvent extracts of Portulacca oleracea against acidified ethanol induced gastric ulcer in rabbits

Portulacca oleracea L. has been used for treatment of different ailments. The aim of this study was to investigate the effectiveness and possible mechanism of action involved in the anti gastric ulcerogenic effect of Portulacca oleracea. Methanolic extract & subsequent fractions (100, 200 and 400 mg/kg) of Portulacca oleracea (P. oleracea) were administered orally to experimental rabbits one hour before oral administration of HCl/ethanol (40:60). Anti gastric ulcerogenic potential of P. oleracea was evaluated by assessment of gastric pH, pepsin, free acidity, ulcer index, mucus content and total acidity. For the investigation of possible mechanism of action malondialdehyde (MDA), histamine, and H + K + ATPase content were determined in the stomach homogenate. Histopathological study of stomach tissue was carried out by H&E dye. Ethyl acetate fraction (EAF) of P. oleracea was the most potent fraction among all fractions that exhibited efficient protection against acidified ethanol mediated gastric-ulcer. The ethyl acetate fraction (EAF) significantly increased the pH of gastric juice, while pepsin and histamine was observed to decrease significantly in comparison to acidified ethanol group (***p ≤ 0.001). The EAF showed moderately H + K + ATPase inhibitory activity. Moreover, it was also observed that EAF decreased the malondialdehyde (MDA) level in the stomach tissue homogenate showing antioxidant effect. Histopathological studies showed that among the tested fractions, EAF significantly prevented acidified ethanol induced gastric mucosal damage. These results showed that mechanism of anti gastric ulcerogenic potential of P. oleracea could be associated with the reduction in histamine level, H + K + ATPase inhibition and reduced MDA level.

Comparison of the therapeutic effects of sildenafil citrate, heparin and neuropeptides in a rat model of acetic acid-induced gastric ulcer

AIMS

The purpose of our investigative work has been to determine whether there can be therapeutic roles in the administration of sildenafil citrate, heparin and several neuropeptides on an animal model where gastric ulcers were induced with acetic acid, and to compare their efficacy.

MATERIALS AND METHODS

The animals were divided into 13 groups, with 4 animals in each. Gastric ulcers was induced in the animals of 12 groups with one untreated group being left as the control (Group I - control; given normal saline (NS)). The other groups were: Group II (ulcer+NS); Group III (5mg/kg sildenafil citrate, low dose); Group IV (10mg/kg sildenafil citrate, high dose); Group V (0.6mg/kg heparin, low dose); Group VI (6mg/kg heparin, high dose); Group VII (20nmol/kg des-acyl ghrelin); Group VIII (40nmol/kg des-acyl ghrelin); Group IX (4nmol/kg acyl ghrelin); Group X (8nmol/kg acly ghrelin); Group XI (20pmol/kg Nesfatin-1); Group XII (15nmol/kg Obestatin) and Group XIII (5nmol/kg Neuropeptide Y). Gastric neuropeptide expression was measured using an immunohistochemical method, and the amount in circulation was detected using ELISA. To compare with no treatment, the controls and other treatment groups, we recorded loss of the surface epithelium of the stomach, erosion, bleeding and inflammatory cell infiltration in the upper halves of the gastric glands.

KEY FINDINGS

The muscularis and the layers beneath it were, however, apparently normal. The gastric mucosa healed with little or no inflammation when sildenafil citrate, low dose heparin, ghrelin, NUCB2/Nesfatin-1, obestatin, Neuropeptide Y were administered.

SIGNIFICANCE

Overall the data indicate that low dose heparin, and especially sildenafil citrate and neuropeptides, can be used clinically as an alternative approach in the treatment of the gastric ulcer.