Gastroprotective and Antioxidant Effects of Royal Jelly on Ethanol-Induced Gastric Ulcer in Rats

Background and purpose: Gastric ulcer is one of the most common diseases of the digestive system. Among the factors that cause gastric ulcers, excessive alcohol consumption is the main reason for stomach mucosal damage; therefore, the experimental model of gastric ulcer caused by ethanol is often used to screen anti-ulcer compounds. There are a wide range of chemical drugs that can be used to treat Gastric ulcers, however, they can also cause side effects. With an emphasis on the need for new drugs with higher efficacy and fewer side effects in the treatment of gastric ulcers, this study was conducted to evaluate the gastroprotective effects of royal jelly on ethanol-induced gastric ulcers in rats. Materials and methods: Sixty Sprague-Dawley rats were allocated to six equal groups. The animals were randomly divided into five equal groups. Groups 1 and 2 were considered as normal control (no treatment) and ethanol control. The animals in group 3 were treated with 10 mg/Kg omeprazole, and in groups 4, 5, and 6 received 1, 2.5, and 5 mg/Kg royal jelly, respectively for three days. On the third day, one hour after the administration of drugs, all animals except the control normal group received ethanol. The animals were euthanized at the end of the experiment and appropriate tissue samples were collected from the stomach for macro- and microscopic examinations as well as measurement of biochemical factors. Results: On macroscopic examination of the glandular tissue of the stomach, the highest amount of hyperemia and bleeding including hemorrhagic longitudinal bands and petechial lesions were observed in the ethanol group, while in the groups pretreated with omeprazole and different doses of royal jelly, the severity and extent of lesions were significantly less. Histopathologically, the most damage was observed in the gastric glandular tissue of rats in the ethanol group, which includes extensive mucosal ulcers, severe hemorrhage in the mucosa, segmental necrosis of the gastric mucosal epithelium, gastric glands disorganization, the loss of chief and parietal cells, severe submucosal edema accompanied by fibrin infiltration in some sections and inflammatory cells infiltration in the submucosa. Although the pattern of lesions in the stomach of rats receiving omeprazole and different doses of royal jelly was similar to the ethanol group, the severity and extent of lesions were less. Omeprazole and royal jelly significantly increased the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), and total antioxidant capacity (TAC) and also significantly decreased the activity of myeloperoxidase (MPO) and malondialdehyde (MDA) as compared with the ethanol group. In comparison between the treated groups, the best therapeutic and protective effects were related to the high dose of royal jelly. Conclusion: Based on the results, royal jelly improved the ulcer index and reduced the histopathological lesions caused by the effect of ethanol on the gastric mucosa. Moreover, it caused a significant increase in the activity of GPx and SOD enzymes, as well as TAC, and a decrease in the concentration of MPO and MDA. The protective effects of royal jelly can be related to the antioxidant activities and cellular protection of this substance.