Determination of nesfatin-1 immune reactivity on the rat stomach after fasting and refeeding

Nesfatin-1, discovered by Oh-I and Shimizu in 2006, is a quite new anorexigenic peptide which is substantially released from stomach and hypothalamus. Nesfatin-1 seems to be responsible for appetite regulation, fasting and satiety cycle, and energy homeostasis. In this study, it is aimed at defining nesfatin-1 immune reactivity of gastric tissue under fasting, and feeding after fasting conditions. In the study, 24 12 week-old adult male Wistar-Albino rats were used. Rats were divided into 4 groups. Rats in Group I, controls, were ordinarily fed; in Group II were deprived of food, and given only water for five days; in Group III were given only water for five days, and fed during the next five days; in Group IV were given only water for five days, and fed during the next seven days. At the end of the experiment, rats were decapitated under anesthesia; and their gastric tissues were separated. Tissues were buried in paraffine blocs; immunostaining procedure was applied for nesfatin-1. In rats fasting for five days, it was observed that in their gastric tissue, surface epithelium degenerated, its integrity was lost, together with local fragmentations and ruptures, spillages occured, extreme expansion and foamy appearance emerged on the lumens of mucous and oxyntic glands. In addition, it was monitored that leukocyte infiltration commenced at the bottom of the glands, and in some areas, the infiltration accompanied the foamy appearance. Furthermore, it was observed that in the oxyntic area cells there were some areas where apoptosis and pyknotic nucleated parietal cells existed. In the fasting group, surface mucous cells and mucous neck cells were more densely stained by PAS(+). Yet decrease in the severity of PAS(+) staining was identified after feeding. After five days of feeding, unlike fasting period, it was identified that the connective tissue increased in lamina propria in some areas, and increased cellular appearance (mononuclear cells) around enlarged gland areas emerged. In parallel with the increase in feeding time (five- and seven-days feeding), gastric tissue gained a similar appearence. After five days of fasting, the number of nesfatin-1 immune-positive cells increased significantly (approximately double), compared to the control. Following the feeding after fasting, it was observed that the number of the cells demonstrating immunoreactivity got close to the control by decreasing progressively. As a result, fasting and feeding after fasting (satiety) conditions lead to changes in nesfatin-1 immunoreactivity. In fasting state, nesfatin-1 immunoreactivity response of gastric tissue changes depending on fasting time. Key Words: Stomach, Nesfatin-1, Fasting, Immunohistochemistry.