Ultrastructural study of the lateral ventricle choroid plexus in experimental hydrocephalus in Wistar rats

Hydrocephalus is one of the most frequent and complex neurological diseases characterized by the abnormal buildup of cerebrospinal fluid (CSF) in the ventricles of the brain, due to an altered CSF dynamics. To detect possible ultrastructural alterations of the lateral ventricles choroid plexus (responsible for the CSF production), rats seven days after birth were submitted to an intracisternal injection of 20 percent kaolim (hydrated aluminum silicate) for the hydrocephalus induction. Twenty-eight or 35 days after injection, injected animals and respective controls were processed for observation under a transmission electron microscopy. Alterations found: presence of concentric cell membrane fragments, larger number of primary and secondary lysossomes, vacuoles, and cytoplasmic vesicles, and an enlargement of the intercellular space and between the basolateral interdigitation of the choroid epithelium. The alterations observed are probably associated to an increase of the ventricular pressure, inducing morpho-functional effects on the choroid plexus integrity.

A hidrocefalia é uma das mais freqüentes e complexas doenças neurológicas caracterizada pelo acúmulo de líquido cefalorraquidiano (LCR) no interior dos ventrículos cerebrais e conseqüente alteração na dinâmica liquórica. Para detectar as possíveis alterações ultra-estruturais nos plexos corióides dos ventrículos laterais (responsáveis pela produção do LCR), ratos sete dias após o nascimento, foram submetidos à indução de hidrocefalia pela injeção intracisternal de caulim a 20 por cento. Após 28 e 35 dias da injeção, estes animais e seus respectivos controles foram processados para observação em um microscópio eletrônico de transmissão. Alterações observadas: presença de membranas concêntricas, maior número de lisossomos primários e secundários, vacúolos e vesículas citoplasmáticas, aumento do espaço intercelular e entre as interdigitações basolaterais das células do epitélio corióideo. As alterações observadas possivelmente estão associadas ao aumento da pressão nos ventrículos, induzindo efeitos morfo-funcionais na integridade dos plexos corióides.

Effects of low-dose phenytoin administered to rats fetuses on developing choroid plexus: kariometric study

The aim of the present study was to determine, by kariometric parameters, the influence of phenytoin, as teratogen, on the epithelial layer of choroid plexus in rats fetuses, using single daily dose ( 75 mg Kg-1 bd.wt.), during gestation GD9 to GD11, and lowest total dose used orally (225 mg Kg-1), to the best of our knowledge. In some of experimental studies in animals, the anticonvulsant drug phenytoin were administered in embriotoxic daily doses (100-1500 mg Kg-1 bd.wt.) increasing concentrations up to 20 times the human therapeutic plasma concentration. There is a significant lack of information regarding the embriotoxicity in pregnancy of these drug, phenytoin, in low doses. Phenytoin was administered in a single daily dose (75 mg Kg-1 bd.wt.) to pregnanty rats in GD9 to GD11 days of gestation, during organogenesis. Histological sections were obtained for analysis of nuclear alterations in the cuboidal epithelium of choroid plexuses of lateral ventricles in the rat fetuses. Eleven kariometric parameters were measured in each of the nuclei. Statistical comparison were made with Mann-Whitney's test. The nuclei of the phenytoin group showed significant reduction of the size parameters : longest axis, mean axis, nuclear volume, nuclear area, nuclear perimeter, ratio of the longest axis to the shortest axis, ratio of the nuclear volume to the nucleararea) but not in shortest axis and shape parameters (contour index, shape factor and eccentricity) . A distinctive pattern of nuclear abnormalities in choroid plexus ephitelium of rat fetuses is associated with the use of low dose of phenytoin during pregnancy. Variations in nuclear size might reflect fundamental nuclear alterations of significance during the process of embriogenesis and could represent teratogenic influence of phenytoin in rats. Even at low dosage and short period of use during gestation, phenytoin can induce embriotoxicity.

Scanning electron microscopy study of the choroid plexus in the monkey (Cebus apella apella)

The cells of the choroid plexus of the lateral ventricles of the monkey Cebus apella apella were examined through scanning electron microscopy at contributing to the description of such structures in primates. The animals were anesthetized previously with 3 percent hypnol intraperitoneally and after perfusion with 2.5 percent glutaraldehyde, samples of the choroid plexus were collected after exhibition of the central portion and inferior horn of the lateral ventricles. The ventricular surface of those cells presents globose form as well as fine interlaced protrusions named microvilli. Among those, it is observed the presence of some cilia. Resting on the choroid epithelial cells there is a variable number of free cells, with fine prolongations which extend from them. They are probably macrophages and have been compared to Kolmer cells or epiplexus cells, located on choroid epithelium. The choroid plexus of the encephalic lateral ventricles of the monkey Cebus apella apella at scanning electron microscopy is similar to that of other primates, as well as to that of other species of mammals mainly cats and rats, and also humans

Ultrastructural alterations of choroid plexuses of lateral ventricles of rats (Rattus norvegicus) submitted to experimental chronic alcoholism

Adult male rats (Wistar lineage) were alcoholized with sugar cane liquor diluted at 30(0) GL during 300 days and sacrificed every 60 days in 5 stages. Samples of choroid plexuses of lateral ventricles were collected and examined at transmission electronic microscope to detect possible ultrastructural alterations and to raise possible pathological correlations. Gradual changes were observed in these animals during all the experiment: dilatation and enlargement of cisternae of Golgi complex, dilatation of RER, presence of digestive vacuoles and a large amount of pinocytic vesicles as well as vesicles with electronlucent content throughout cytoplasm, as well as an enlargement of intercellular space between basolateral interdigitation of the cells and of the connective tissue. The changes observed in the epithelium and connective tissue of choroid plexuses specially in 240 and 300 days of treatment are presumably due to a disturbance in hydroelectrolitic homeostasis, contributing to several morpho-functional disturbs of central nervous system. No changes were observed in the control group animals.

Ultrastructural changes of the choroid plexus of the lateral ventricles of rats, rattus norvegicus, submitted to experimental chronic alcoholism, followed by alcohol withdrawal

Cuarenta ratas machos adultas se dividieron en dos grupos de 20 animales cada uno (grupos control y experimentales). El grupo experimental recibió alcohol de caña de azúcar comercial, marca "51 Pirassununga", diluida a 30º g/L como dieta líquida por un período de 240 días y agua potable por los siguientes 60 días. Los animales se sacrificaron después de 60, 120, 180, 240 y 300 días de tratamiento. Se observaron varios cambios morfológicos en el grupo experimental de animales de hasta 240 días de tratamiento, encontrándose dilatación de las cisternas del retículo endoplasmático rugoso, espacios intercelulares aumentados, espacios entre las interdigitaciones basolaterales de las células, inflamación del tejido conjuntivo y presencia de una gran cantidad de células pinocíticas, de vacuolas digestivas y de vesículas con contenido electrolúcido a lo largo del citoplasma. Después de 300 días de tratamiento, el grupo experimental de animales presentó una regresión importante de los cambios descritos. No se observó cambios en el grupo de animales control

Light & electron microscopic structure of choroid plexus in hydrocephalic guinea pig.

With a view to study the morphological changes, if any, in the choroid plexus in association with hydrocephalus, obstructive hydrocephalus was created in 15 young guinea pigs. The choroid plexus of the control group (n = 16) showed high cuboidal or columnar epithelium. The mitochondria of the choroid plexus ependyma converged towards the apex. Varying concentrations of Golgi complex and rough surfaced endoplasmic reticulum (RER) were noticed in the apical part of the epithelium. Subsurface cistern-like structures and occasional formation of vesicles from the adjacent cells of the epithelium were observed. Basolateral infoldings were numerous and compactly arranged. Most capillaries had their fenestrated part facing the base of the epithelium. Choroid plexus of hydrocephalic guinea pigs showed flattened epithelial cells with less extensive Golgi complex and RER. Mitochondria were found lying parallel to the flattened nucleus. Intercellular spaces were dilated with loosely packed basolateral infoldings. Most of the features observed in the hydrocephalic guinea pig are indicative of reduced activity of the choroid plexus epithelium.

Morphometry of mitochondria in the choroidal ependyma of hydrocephalic guineapigs.

Fifteen young guineapigs were made hydrocephalic by intracisternal injection of kaolin and 16 guineapigs were used as control. Volume, number and surface areas of both the outer and inner membranes of the mitochondria of the choroidal ependyma of these animals were studied, using a coherent multipurpose test system. Volume, number and surface area of the outer membrane of the mitochondria did not show any significant difference between the two groups. However, surface area of the inner membrane of the mitochondria including cristae showed a significant decrease in the hydrocephalic animals. This reduction in the surface area could probably be attributed to the reduced activity of the choroidal ependymal cells in obstructive hydrocephalus.

Atypical cilia in the choroid plexus of guineapig.

Ultrastructural study of choroid plexus of normal and kaolin induced hydrocephalic guineapigs showed clusters of cilia arising from the apical part of some of the epithelial cells. Some of these cells had typical 9 + 2 cilia, while most of the control and the hydrocephalic groups showed 9 + 0 type of cilia. These atypical (9 + 0 type) cilia of choroidal epithelium differ from the primary cilia of other mammalian tissues in that, clusters of long cilia arise from a single cell and have no associated centrioles within the cytoplasm. They may be motile and sensory (osmoregulator or pressure sensor or both) in nature.