Study On The Characterization Of Structure And Distributive Changes Of Mucosal Immunity-associated Cells In Small Intestine Of The Yak

Yak is unique animal species in china,alpine meadow for food.Providing irreplaceable life material and production material for local nomads,which is the important stockbreeding economy pillar in local.Gastrointestinal mucosa is not only the animal digestion and absorption of nutrients place,but also have immune barrier function.In order to reveal characterization of the structure and the distribution changes of small intestinal immunity in the yak.Study of the morphological structure and intraepithelial lymphocytes,goblet cells, plasma cells and mast cells of small intestine in the yak were investigated by histochemical,the scion image software analysis techniques and the electron microscope technique.The results showed that there are mucousmembrane,submucosa, tunica muscularis and serosa in small intestine of the yak.The ratio of high/crypt depth(Duodenum 3.0±0.5,Jejunum 2.1±0.2,Ileum 1.4±0.3) and the thickness of tunica muscularis (Duodenum 2242.2±155.4μm,Jejunum 1155.7±47.9μm,Ileum 1974.8±86.4μm)of duodenum is the highest;the high of villi ( Duodenum 1468.7±53.3μm,Jejunum 1828.4±112.5μm,Ileum 1336.0±84.5μm ) and the crypt depth ( Duodenum 553.3±30.4μm,Jejunum 947.6±85.5μm,Ileum 781.0±52.2μm) of jejunum are the longest and highest;the high of villi, the crypt depth, the ratio of high/crypt depth and the thickness of tunica muscularis in each segment of small intestine,which significantly differed (P <0.01).The number of intraepithelial lymphocyte(Duodenum 31.4±3.9,Jejunum 25.6±3.0,Ileum 24.2±3.3), goblet cell(Duodenum 18.0±2.1,Jejunum 14.7±1.6,Ileum 6.5±1.5)and mast cell(Duodenum 39.3±4.9,Jejunum 35.5±4.2,Ileum 25.4±3.9) gradually reduce from duodenum,jejunum to ileum, but the number of plasma cell(Duodenum 3.7±1.1,Jejunum 8.1±1.5,Ileum 10.4±2.0)exhibits an increasing trend,which significantly differed(P<0.01). In the electron microscope,there are tight junction,gap junction and hemidesmosome,a lot of microvillus in small intestine of the yak.The nuclei of intraepithelial lymphocytes are larger and cytoplasms are less.Goblet cells are typical goblet shape,its top become larger,because of a number of secretory granules;Plasma cells are circular or elliptical, the chromatin is distributed along the nuclear membrane,cytoplasms are richer in endoplasmic reticulum;Mast cells are elliptical, there are strong electron density particles in its cytoplasm.Digestion and absorption of arctic-alpine pasture are greatly enhanced by the structure of small intestine in the yak; there are regular distribution of mucosal immunity-associated cells in each segment of small intestine, to provide good immune barrier function for small intestine.