Study On Structural Characteritics Of Zebrafish Brain

As an experimental model animal,zebrafish(Danio rerio)has many valuable features,such as its prolific reproduction,the external development and the transparent embryo.In recent years,the zebrafish has been used in development biology,genetics,behavioral science,environmental monitoring,cancer biology and the drug design as a prime model animal.What's more,the zebrafish is also very popular as a good model in vivo study on morphological and functional development of nervous system.Scientists pay more and more attention to the zebrafish in the field of neurodegeneration research.Although there are many differences between the human's and zebrafish's central nervous system,while the types of neurons and glial cells and disease-related genes in zebrafish are very similar to those in human beings.The research in morphological point on zebrafish nervous system were little done before,especially the ultrastructure of zebrafish nervous system.In this research we established a morphological atlas of zebrafish brain.Thus a comprehensive whole zebrafish brain atlas which can provide a reference data for the further study of zebrafish brain is constructed.Experiment ? Microstructure of zebrafish brainThe histology of zebrafish brain were observed by light microscopy.Zebrafish brain consists of telencephalon,diencephalon,mesencephalon,cerebellum and medulla oblongata.The telencephalon shaped long oval,includes the olfactory bulbs,olfactory lobes and cerebral hemispheres.The differentiation of olfactory lobe and olfactory bulbs were obviously,a pair of olfactory nerves emerge in front of olfactory bulbs,olfactory stems extend to cerebral hemispheres from the back of olfactory bulbs.Back to the diencephalon arises a pineal gland,a heart-shaped funnel emerges in the centventral part,and heart-shaped pituitary gland emerges in the front of diencephalon.Optic lobe associated with developed vision is inflated.The developed cerebellum may be related to active life habits.The anterior part of medulla oblongata is prorupt.And 147 nuclei can be observed in zebrafish brain of this experiment.Experiment ? Ultrastructure of zebrafish brainIn order to understand zebrafish brain more deeply and augment current neurobiological research,we observed ultrastructure of nerve cells,blood-brain barriers and synapses through transmission electron microscopy(TEM).The study has been carried on adult AB type zebrafish,under the TEM,we can observe neurons that include mitral cells,granulocyte,purkinje cells and golgi cells.Synapse includes presynaptic membrane,synaptic cleft and postsynaptic membrane,which can be subdivided into axodendritic synapse,axosomatic synapses and axoaxonic synapses.Blood-brain barrier(BBB)is composed of three successive layers including the capillary endothelial cell,the basal lamina and the perivascular glial endfeet.And more BBBs were distributed in the telencephalon than other parts of zebrafish brain.Experiment ? Immunohistochemistry in zebrafish brainBy doing immunohistochemistry on zebrafish brain,we observed the BDNF and CD34 were negative in cerebellum and diencephalon.But they were positive in optic tectum.The positive site was at the junction of stratum centrale and stratum marginale,and the CD34 positive reaction was more obvious.