Fatma Abd Elhalim Mahmoud, Khalid S Hashem, Asmaa Mohammed M Hussein Elkelawy

No dose of aspirin is free of bleeding risk. Even at a dose as low as 75 mg/day, the risk of upper gastrointestinal bleeding is twice as high as among nonusers. Nanoemulsions (NEs) are emulsion systems with droplet size in nanometer scale in which oil or water droplets are finely dispersed in the opposite phase with the help of a suitable surfactant to stabilize the system. The objective of this study was to determine the effect of aspirin NE in comparison to conventional aspirin. A total of 24 male rats were used in the study and arbitrarily assigned to four groups. Group 1 was the control group, and was given saline. Group 2 was given blank NE 1.5 mL/kg orally. Group 3 was given aspirin 30 mg/kg body weight orally. Group 4 was given aspirin NE 30 mg/kg body weight orally. Rats were killed, and gastric tissue was quickly excised after dissection of the animals. The tissues were divided into three pieces. The first one was kept in formalin 10% for pathological investigation. The second piece was kept in liquid nitrogen for molecular investigation. The third piece was homogenized in ten volumes of ice-cold phosphate-buffered saline (pH 7) using a Teflon homogenizer until a uniform suspension was obtained. The homogenate was centrifuged at 4,000 rpm for 30 minutes at 4°C to separate the supernatant from cellular debris. The supernatant was then used for the estimation of biochemical assays. The present study shows that aspirin has a toxic effect on the stomach as a result of inducing marked oxidative damage and the release of reactive oxygen species. This was shown by the significant increase in TNFα, iNOS, prostaglandin E2, and malondialdehyde levels, and also a significant decrease in glutathione, glutathione reductase, glutathione peroxidase, catalase, and superoxide dismutase. In the aspirin-treated group compared to the control group, the NE had a protective effect on the stomach and caused less injury than aspirin, indicated by significant decreases in TNFα, iNOS, prostaglandin E2, and malondialdehyde levels, and also significant increases in glutathione, glutathione reductase, glutathione peroxidase, catalase, and superoxide dismutase. The biochemical results were confirmed by histopathological studies. Aspirin nanoemulsion has less toxic effect on the gastric mucosa compared to ordinary aspirin. This can be indicated by the increase of the antioxidant activity and the decrease of the inflammatory mediators in the gastric tissue.