METHODS: The rats were divided into seven groups according to their pretreatment: an untreated control group, an ulcer control group, a reference control group (20 mg/kg omeprazole), and four experimental groups (50, 100, 200, or 400 mg/kg of extract). Carboxymethyl cellulose was the vehicle for the agents. Prior to the induction of gastric ulcers with absolute ethanol, the rats in each group were pretreated orally. An hour later, the rats were sacrificed, and gastric tissues were collected to evaluate the ulcers and to measure enzymatic activity. The tissues were subjected to histological and immunohistochemical evaluations.
RESULTS: Compared with the extensive mucosal damage in the ulcer control group, gross evaluation revealed a marked protection of the gastric mucosa in the experimental groups, with significantly preserved gastric wall mucus. In these groups, superoxide dismutase and malondialdehyde levels were significantly increased (P < 0.05) and reduced (P < 0.05), respectively. In addition to the histologic analyses (HE and periodic acid-Schiff staining), immunohistochemistry confirmed the protection through the upregulation of Hsp70 and the downregulation of Bax proteins. The gastroprotection of the experimental groups was comparable to that of the reference control medicine omeprazole.
CONCLUSIONS: Our study reports the gastroprotective property of an ethanolic extract of C. olitorius against ethanol-induced gastric mucosal hemorrhagic lesions in rats.
METHODOLOGY/PRINCIPAL FINDINGS: Sprague Dawley rats were separated into 7 groups. Groups 1-2 were orally challenged with carboxymethylcellulose (CMC); group 3 received 20 mg/kg omeprazole and groups 4-7 received 50, 100, 200 and 400 mg/kg of ethanolic leaf extract, respectively. After 1 h, CMC or absolute ethanol was given orally to groups 2-7. The rats were sacrificed after 1 h. Then, the injuries to the gastric mucosa were estimated through assessment of the gastric wall mucus, the gross appearance of ulcer areas, histology, immunohistochemistry and enzymatic assays. Group 2 exhibited significant mucosal injuries, with reduced gastric wall mucus and severe damage to the gastric mucosa, whereas reductions in mucosal injury were observed for groups 4-7. Groups 3-7 demonstrated a reversal in the decrease in Periodic acid-Schiff (PAS) staining induced by ethanol. No symptoms of toxicity or death were observed during the acute toxicity tests.
CONCLUSION: Treatment with the extract led to the upregulation of heat-shock protein 70 (HSP70) and the downregulation of the pro-apoptotic protein BAX. Significant increases in the levels of the antioxidant defense enzymes glutathione (GSH) and superoxide dismutase (SOD) in the gastric mucosal homogenate were observed, whereas that of a lipid peroxidation marker (MDA) was significantly decreased. Significance was defined as p<0.05 compared to the ulcer control group (Group 2).