Morphological Observation On The Choroid Plexus And Epiplexus Cells Of Rat Lateral Ventricles

Cerebrospinal fluid(CSF)circulation,known as human third circulation,plays an very important role in the pathogenesis and prevention of the central nervous system disease such as hydrocephalus,cranial pressure,intracranial hemorrhage,subarachnoid hemorrhage.The ventricular system choroid plexus,especially lateral ventricle choroid plexus,is the main place of produce cerebrospinal fluid,the cerebrospinal fluid accounts for about 80% ~ 85% of the total and also the main site of the blood-brain barrier.The central nervous diseases such as Alzheimer disease(AD),may be close relationship with cerebrospinal fluid circulation is normal or not.The structural changes of choroid plexus,will directly affect the production of cerebrospinal fluid,resulting in CSF circulation obstacle.Object: To observe the subtle and ultra-structural characteristics of the rat lateral ventricle choroid plexus and epiplexus cells,providing morphological basis to explore its functional meaning.Methods:1 Experimental animals and materialsChoosen five adult male SD rats,10 months,weight 250-300 g,provided by animal experiment center of Hebei Medical University.Rats were drawn by aortic perfusion fixation for light and electron microscope preparation of tissue samples.2 Sample preparation and observation for light microscopeThe aldehyde fixative fixed rat brain is given the concentration gradient from low to high ethanol dehydration,hyalinized xylene,embedded in paraffin,tissue sections,and then do routine HE staining and observe by light microscope,to show the fine structural characteristics of lateral ventricle choroid plexus.3 Sample preparation and observation for SEMThe tissue samples of fixed choroid plexus,then prepare the conventional scanning electron microscope(SEM)sample.By scanning electron microscope,reveal the surface structural characteristics of rat choroid plexus.4 Sample preparation and observation for TEMTake aldehyde fixed choroid plexus tissue samples for routine transmitssion electron microscope(TEM)sample preparation,observation on the ultra-thin tissue slice by transmission electron microscope,reveal the ultrastructural features of the choroid plexus and epiplexus cells.Results:1 HE stained paraffin embedded tissue sections by light microscope observation showed that: The structure of the rat choroid plexus has three components: capillary network in the center,around for connective tissue,the outer most cover with ependymal epithelium so as choroid plexus epithelium.Capillary lumen is irregular,pipe diameter sizes and tube wall surrounded by monolayer endothelial cells,endothelial cell nuclei in fusiform,often convex to the lumen.The surrounding stroma cells in the connective tissue.Choroid plexus epithelial cells arranged closely,a short columnar or cuboidal,larger nucleus,round and dyeing uniform.2 SEM observation showed that: on the surface of rat lateral ventricle choroid plexus,there present parallel arranged as fold or crest sample forms.Closely packed between each choroid plexus epithelial cell,its free surface(ventricular surface)irregular shape,round,oval,or polygon.Observed under magnification,the free surface of choroid plexus epithelial cells was a large gathering of microvilli,including a few numbers of cilia.The epiplexus cells prostrate on the surface of microvillus,shaped like a spider,the pseudopodia sample protrusions from the cell body.3 TEM observation showed that: there are gap junctions between rat lateral ventricle choroid plexus adjacent epithelial cells,near the free edge is closely connected.The epiplexus cells protruding pseudopodia prostrate on the microvilli.In the epiplexus cell,often existing a large number of primary lysosome,secondary lysosomes or phagosome.Conclusion: The observation shows that rat choroid plexus is composed of three kinds of structural components: the capillaries as the center,surrounding the loose connective tissue around,appearance is lined by choroid plexus epithelium.There were a lot of microvilli on the free surface of choroid plexus epithelial cells,which have active secretion function.There was close connection between the top of adjacent epithelial cells,blocking intercellular space was considered as the main structural basis of blood-brain barrier.Epiplexus cells as strangers in the land of intraventricular mononuclear macrophage system,is responsible for cleaning up the harmful material of the cerebrospinal fluid.