Protective Effects of Small-Molecule Oligopeptides Isolated from Tilapia Fish Scale on Ethanol-Induced Gastroduodenal Injury in Rats

Peptic ulcer has a serious impact on people's health around the world, and traditional medicines can cause adverse reactions. This study investigated the protective effects of tilapia collagen oligopeptides (TCOPs) on gastroduodenal injury. Seventy-two specific pathogen-free (SPF) male Sprague Dawley (SD) rats were randomly divided into six groups according to body weight: normal control group, ethanol group, whey protein group (500 mg/kg BW), and three TCOPs dose groups (250, 500, 1000 mg/kg BW). After intragastric administration for 30 days, the acute gastroduodenal injury was induced by anhydrous ethanol (5 mL/kg, intragastrically) in all groups except the normal control group. Biomarkers in gastric and duodenal tissue and serum were measured. Furthermore, western blot was used to detect the expression of apoptosis-related proteins. The results showed that the administration with TCOPs significantly reduced gastric and duodenal ulcer index, increased gastric juice pH, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities, along with the reduction of malondialdehyde (MDA) contents. TCOPs decreased tumor Necrosis Factor-α (TNF-α), interleukin-1β (IL-1β), and myeloperoxidase (MPO) levels, while interleukin- 10 (IL-10) levels were increased. Furthermore, pepsinogens 1 (PG1), pepsinogens 2 (PG2), gastrin (GAS), and the pepsinogen ratio (PGR) were decreased, the prostaglandin E2 (PGE2) and NO contents were increased after TCOPs intervention. Moreover, TCOPs up-regulated the expression of Bcl-2 and inhibited the expression of Bax and Caspase-3. In conclusion, TCOPs have protective effects on ethanol-induced gastroduodenal injury through gastrointestinal mucosal microcirculation promotion, antioxidation, anti-inflammation, and anti-apoptosis mechanisms.