Ghrelin, Interferon-γ Receptor And Estrogen Receptor-α Immunopositive Substances In The Gastrointestinal Tract Of Rats Under Different Nutritional Condition

With the research in animal nutrition and gastrointestilal mucosal immune system, making the function of gastrointestinal neuroendocrine becomes more and more interested to researchers. Gastrointestinal peptides regulate secretion, absorption, blood flow and cell nutrition, immunization and other functions of digestive tract with other biologically active substances such as cytokines, hormones and their receptors.Ghrelin is a newly discovered growth hormone secretagogue receptor (GHS-R) endogenous ligand. It can strongly stimulate GH release through its receptor and promote animal food intake. Interferon-γreceptor (IFN-γR) is a cytokine with antiviral activity; studies have shown that it also plays an important role in gastrointestinal tract mucosal immune regulation. Estrogen play a vital role in reproduction through its receptor (ER), above that, it can also regulate gastrointestinal function. In this study immunohistochemical SP method was used to locate Ghrelin,γ-interferon receptor (IFN-γR) and ER-αimmunopositive cells in the stomach and intestine of standard nutrition, low nutrition and high-nutrition diet fed rat. The major findings were as following:1. Ghrelin positive cells were mainly distributed in fundus glands and layers of small intestine. Ghrelin expression in stomach was significantly higher than the small intestine (P<0.01). Ghrelin expression in the low nutrient treatment group was higher than the standard nutritional group and high nutrition groups (P<0.05). The expression of Ghrelin increased as feeding time prolong. Ghrelin expression reduced (P<0.05) when low-nutrition group returned to standard conditions. 2. IFN-γR expression was weak in the standard group (2 weeks). Rising to 4 weeks, IFN-γR was showed in fundus gland, intestinal glands and submucosa. There are more IFN-γR positive cells in the stomach high-nutrition treatment group than the low nutrition treatment group, but the difference was not significant.3. ER-αpositive cells were mainly distributed in the gastric epithelium, gastric glands and intestinal glands, especially the relevant secretory cells and immune cells. The expression of ER-αrising as feeding time increased (P<0.01). The expression of ER-αin low-nutrition group was significantly lower than the high nutrition group and standard group (P<0.01). The low recovery group ER-αexpression did not change in the stomach, but in the small intestine compare to the low nutrional group. The expression of ER-αin high nutritional recovery group were lower than 2 weeks of high-nutrition group (P<0.05).These results suggest that in the high nutrient condition, Ghrelin was secrete to reduced food intake and it is a short time-sensitive possesse. Food stress and sustained stimulation can stimulate expression of the IFN-γreceptor in stomach and small intestine secretion-related cells and immune cells. ERαexpression in the gastrointestinal tract and nutritional status of animals was a positive correlation. Ghrelin and ERαplay a major role in reducing animal stress response and mucosal immunity in animal gastrointestinal tract.