HISTOPATHOLOGICAL CHANGES IN THE STOMACH MUCOSA OF RATS FED WITH CARPET SHELL CLAM (Ruditapes decussatus)

Abstract

Free radicals are produced in cells by cellular metabolism and exogenous agents. These specie reacts with biomolecules in cells, including DNA, proteins, lipids and carbonhydrates. The resulting oxidative damage to DNA, is implicated in mutagenesis, carcinogenesis, and aging. Heavy metals, industrial and household wastes and pesticides are threats for the aquatic ecosystem. Polluted water sources are streaming into the seas and cause pollution in these systems. Dardanelles is exposed to pollution from the Marmara and Black Sea. Our previous studies demonstrated that the water and mollusc from certain regions of the Dardanelles contained heavy metal salts. The purpose of the study is to demonstrate DNA damage and the histopathologic changes in the gastric tissues of rats which are fed with carpet shell clam that are collected from the Çardak Lagoon (Çanakkale, Turkey). Four groups of rats are included in the study, group 1 (n=6), control group fed with standard rat food, group 2 (n=6), 75%  carpet shell clam and 25% standard rat food daily, group 3 (n=6), 75% carpet shell clam and 25% standard rat food every two days, group 4 (n=6), 75%  carpet shell clam and 25% standard rat food every three days. After the routine histopathologic processing all gastric tissue samples are evaluated in terms of 8-hydroxy-2' -deoxyguanosine (8-OHdG) immunoreactivity with light microscopy and image analysis software. No histopathologic differences found in standard hematoxylin-eosin stained gastric tissue samples of the control group. Mucosal specimens of the second, third and fourth groups showed mild mononuclear inflammation in favor of chronic gastritis. In immunohistochemical staining, 8-OHdG immunoreactivity in gastric epithelial cells.  8-OHdG immunoreactivity was negative in stomach tissues in all groups.  There was no statistically significant difference between the groups that were fed every day, every other day and every three days with clam (p>0.05). The results of our studies showed that rats fed more with carpet shell clam could produce gastritis in the stomach.