Morphology And Histochemistry Of Mast Cells In Bullfrog (Rana Catesbeiana)

Objective: To study the histochemistry and morphology of mast cell in ranid;Methods: Based on the anatomical histological observation of bullfrog, the histochemistry and morphology of bullfrog mast cells was studied through histological technique(routine and immune histochemistry), morphological technique (light microscopy and transmission electron microscopy) and fluorophotometer. Results: 1. The anatomical histological character of bullfrog was described. 2. Mast cells were distributed in main tissue and organs of frog, especially in the tongue, spleen, intestine and mesentery . There were large difference in number and morphology and they intended to be adjacent to nerves and blood vessels with some within them.; Frog mast cells contained numerous characteristic cytogranules, and they were often seen in perineurium . Some mast cells were very closed to perineurium even contacted perineurium by protuberance; 3. Both Bouin's fluid and Carnoy's fluid were proved to be the excellent fixatives. Somewhat like the mucosal mast cells (MMC) in mammals, however, when fixed in neutral buffered formalin (NBF) the staining of bullfrog mast cells in the lamina propria of intestine was significantly blocked. It is interesting that toluidine blue was the good dye for bullfrog mast cell staining which made much more cells stained than Alcian blue did. 4. Some mast cells in the sections of tongue, intestine and lung fluoresced strongly when stained with acridine orange which suggested that they may contain heparin proteoglycan. 5. A murine monoclonal antibody (AA1), raised against human mast cell tryptase , was used in an indirect immunoperoxidase technique to stain the paraffin sections of intestine, spleen and tongue collected from bullfrogs ( Rana catesbeiana ) and gullet cancer tissue from an adult man. An excellent cross-reaction of the antibody AA1 with frog mast cell tryptase was obtained. In frog tissues the tryptase-positive mast cells mainly lie in lamina propria of intestine, a little were distributed in the base of intestinal villus and around submucosal glands of tongue; 6. The frog mast cells contained histamine by fluorophotometer, and the histamine content of intestine were of obvious differences among seasons . Discussion: The histochemistry and morphology of bullfrog were studied. It was firstly confirmed that the frog mast cells contain tryptase in their cytoplasm . Meanwhile, it was also demonstrated that the frog mast cells contain histamine and heparin proteoglycan. The closed relation between mast cell and nerve was confirmed again. the numous mast cells in tongue, intestine and spleen indicated that the possible function of mast cells in host defence immune. Conclusion: There were much similarity between frog mast cells and mammal mast cells. It was very likely that bullfrog can be empoldered to be ideal experimental animal to study mast cell biology. Especially in studies on the reaction between mast cells and nerve or blood, function of histamine,neutral proteinase and other bioactive substance in mast cells, or heterogeneity and biological significance of mast cells, Bullfrog may be very significant.