Studies On The Histology And Immunohistochemistry Of Digestive Tract Of Elopichthys Bambusa

The digestive tract of Elopichthys bambusa was studied on anatomy,histology and immunohistochemistry in this paper.E.bambusa has no stomach but with a Z-shape intestine which became thinner and thinner from foregut to hindgut.There was a linear relationship between the length of intestine and body length with a formula of y= 1.6587x+5.4506(R~2=0.9371).The digestive tract was divided into bucco-pharyngeal cavity,esophagus,foregut,midgut and hindgut.The wall of digestive tract was composed of a mucosa,submucosa,muscularis and serosa.Compared with the esophagus,the mucosal folds in the intestine were abundant with numerous branches and arranged tightly. The mucosa in the intestine was lined by a simple columnar epithelium with abundant goblet cells and obvious microvilli.The height of mucosal folds,thickness of submucosa, circular and longitudinal muscularis,and the number of goblet cells decreased gradually from foregut to hindgut.The pattern and distribution of mucous cells in the digestive tract of E.bambusa were investigated using periodic acid-Schiff(PAS) with AB(pH 2.5),alcian blue(AB) at pH 1.0 and 2.5,aldehyde fuchsin(AF) with AB(pH 2.5),and PAS methods.According to AB-PAS(pH 2.5),four types of mucous cells(Ⅰ,Ⅱ,ⅢandⅣ) were observed.The four types of mucous cells were distributed in every part of the digestive tract.In the esophagus,type(ⅡandⅣ) while in the whole intestine type(ⅢandⅣ) were abundant.The statistical result showed that:the number of mucous cells decreased gradually from foregut to hindgut and the distributive densities were 447.5±72.7/mm~2, 410.48±63.15/mm~2 and 382.14±72.14/mm~2,respectively.A sequence of procedures utilizing Alcian blue at different pH values(pH 1.0 and 2.5) showed the presence of acid mucins which included sulphated and carbonic mucosubstance in the digestive tract of E. bambusa,and meanwhile abundant acid mucins(the content of carbonic mucosubstance was more than the sulphated one) were observed in the digestive tract by AF-AB(pH2.5) method.In this paper,identification and distribution of some endocrine cells in the digestive tract of E.bambusa werestudied using the Strept Avidin-Biotin Complex(SABC) staining technique.Positive reactions were obtained with antisera against gastrin and glucagon.No immunoreactivities were found with antisera against somatostatin and 5-hydroxytryptamine(5-HT).Gas-cells with the round,oval,spindle and pyramid shape were found in the whole intestine and in the foregut abundant.Glu-cells,round and oval shape,were only found in the hindgut.The argyrophil cells in the digestive tract were studied by Grimelius silver staining method and the results showed that there were no argyrophil cells in the digestive tract.