Fig. 3.

Representative gross macroscopic and microscopic appearance (using H&E staining) of the gastric mucosa pretreated with (A) vehicle (saline) or (B) curcumin (50 mg/kg i.g.) 30 min before per os instillation of 75% ethanol (1 ml/rat) and curcumin-pretreated gastric mucosa of rats treated with L-NNA (20 mg/kg i.p.) applied alone (C) or combined with l-arginine (200 mg/kg i.g.) (D) and exposed to 75% ethanol. The severe gastric haemorrhagic lesions are clearly visible in the gastric oxyntic mucosa pretreated with vehicle (saline) and exposed to 75% ethanol (A1). The gastric mucosal lesions were markedly reduced in gastric mucosa pretreated with curcumin (50 mg/kg i.g.) and exposed to ethanol (B1). In rats pretreated with L-NNA (20 mg/kg i.p.) and administered curcumin (50 mg/kg i.g.), the protective effect of curcumin against ethanol injury was lost (C1). When l-arginine (200 mg/kg i.g.) was administered with L-NNA, a curcumin-induced reduction in the formation of haemorrhagic gastric lesions was observed (D1). In the vehicle-pretreated rats compromised by ethanol, a severe disruption of gastric mucosa, accompanied by the loss of glandular architecture and leucocyte infiltration, is observed (A2). Of note, in curcumin-pretreated gastric mucosa, relatively mild disruption of gastric mucosa along with mild oedema and partial preservation of glandular structure can be observed in comparison with vehicle-control (B2). The loss of glandular structure and the presence of deep mucosal lesions were observed in gastric mucosa of rats treated with a combination of L-NNA and curcumin (C2). In contrast, the mild disruption of gastric mucosa and a partial restoration of glandular structure along with mild signs of inflammation were observed in gastric mucosa of l-arginine-treated rats administered a combination of L-NNA and curcumin and compromised 30 min later by 75% ethanol (D2)