The choroid plexus in experimental hydrocephalus

✓ Experimental hydrocephalus was created in dogs by injection of kaolin into the cisterna magna. One month after the kaolin injection, ventriculojugular shunts were performed on certain of the hydrocephalic dogs. Shunted hydrocephalic dogs were killed 1 day or 1 week after placement of the shunt. Cerebrospinal fluid (CSF) pressures were measured prior to the kaolin administration and/or 1 month post-kaolin injection and/or after the shunting procedure. Choroid plexuses from control, hydrocephalic, and shunted hydrocephalic dogs were examined by light and electron microscopy. The hydrocephalic dogs had choroid plexuses with a flattened epithelium, compacted cytoplasm, and multiple large vacuoles usually containing small, rounded membrane-bound structures; it was postulated that these vacuolar structures were dilated multivesicular bodies possibly related to CSF resorption. Choroid plexuses from hydrocephalic dogs examined 1 day post-shunt closely resembled choroid plexuses from the control dogs. Intracytoplasmic, apical lipoid inclusions, 1.0 to 6.0 µ in diameter, were noted within many choroidal epithelial cells of dogs shunted for 1 week. This change was probably related to the trauma of shunt insertion. It was concluded that the morphology of the canine choroid plexus returned to normal 1 day after the ventriculojugular shunt.