Endothelium Of Arachnoid Villus Alters Morphologically With CSF Absorption Changing In Hydrocephalus Animals

Backgrounds and ObjectsHydrocephalus is a common disease of neurosurgery. Since the ventricle-peritoneum shunting and the third ventriculostomy are performed world-widely, the overall prognosis of hydrocephalus is unsatisfied. For instance, 40.7% of the patients, who accepted the v-p shunting operation in 2000 in the United States, were admitted for the diagnosis of "shuntingmalfunction". It is need to investigate the secretion, circulation, and the absorption of the CSF. What is the affection each other of these three factors? For instance, would the absorption ability alter when the CSF circulation is obstructed? On account of this logic, the research will setup the hydrocephalus model of canine, study the micro-structures of the arachnoid villus and the morphological alteration of the endothelium of the arachnoid villus on hydrocephalus condition. The isotope tracer will be injected into the subarachnoid space, then the blood samples will be collected from the jugular vein of the canine, thus we can get the message that the alteration of the absorption ability of the arachnoid villus on the different stages of hydrocephalus. The research will elucidate the secondary alterations of arachnoid villus morphologically and the absorption ability on hydrocephalus condition, and provide new ideas for the treatment of hydrocephalus.Materials and methodsThe first portion of the thesis emphasizes on the morphological alteration of the endothelium of arachnoid villus. 26 hybrid canines was used for the study. 2 of them were used for the HE-staining research. Another 24 canines were separated into 4 teams. The first team was the control team, which accepting isotonic saline injection in the fourth ventricle. The 2nd, 3rd, and 4th team (acute, sub-acute, and chronic team) were the hydrocephalus teams, which accepted silicon oil injection into the fourth ventricle. The scoring of Tarlov was performed post-operatively. The 2^nd, 3^rd, and 4^th team was sacrificed separately after 3 days, 2 weeks, and 12 weeks post-operatively. The MRI scanning of the brain was performed before thesacrifice for confirming of the hydrocephalus. The 2 HE-staining animals were perfused with 4% formaldehyde, then specimen was collected. The specimen for electron microscope study was collected after perfusion of 2% glutaraldehyde. The specimen for immunofluorescence histochemistry was collected after perfusion of Zamboni liquid. Expression of CD-31 and von Willlebrand factor of the endothelium of the arachnoid villus were studied by immunofluorescence histochemistrically. The results were compared by one way ANOVA analysis.The second portion of the thesis emphasized on the alteration of the function of CSF absorption. 20 canines were separated into 4 teams. Team 1 was the control team, and the team 2, 3, and 4 were the hydrocephalus teams. The cribriform plates of all the animals were obstructed before the further procedure. One milliliter isotonic saline including 50 n Ci 3H2O were injected into subarachnoid space in different post-operation time (acute team: 3 days, sub-acute team: 2 weeks, chronic team: 12 weeks). The jugular veins were anatomized for blood collection in post-injection 1 hour, 4 hour, 8 hour, 16 hour, and 48 hour. The content of 3H2O in samples of blood were detected by Liquid Flaring Count Implement. The mean absorption curves of the teams were described. The areas under the absorption curves (AUC) were calculated for comparing the CSF absorption abilities in different teams. The differences were compared by one way ANOVA analysis.Results1) The hydrocephalus model was constituted satisfactorily by injection of silicon oil. The disease model can reflect the disease of human.2) The brain MRI scan showed the ventricles of the canines enlarged progressively after injection. In chronic phase, the parenchyma of brain had become atrophic.3) Most of the arachnoid villus of the canine distributed in the former sagital sinus, especially nearing the central veins entrances.4) The HE-staining research elucidated that the arachnoid villus of canine is constructed by the endothelium layer, the fibril capsule, the arachnoid cell layer (cup cell cluster) , and the central core. Some of the villus are ball-shape, yet others are lobulated or creeping. Another extraordinary situation is the defecting of the fibril capsule.5) The immunofluorescence histochemistry staining of CD-31 showed that all the endothelium expressed positive, including the endothelium of the villus. The expressions were same in all four teams.6) The immunofluorescence histochemistry staining of von Willebrand factor showed that the expression of the endothelium of the villus is diminished than the normal sinus wall. The expressions were different in four teams.7) The second portion of the thesis fund that the absorption of the tritium oxide injected into the arachnoid space presented a skewness distribution curve with single peak. In the control team and the acute phase team, the concentration of the tritium oxide peaked at the 8 hour point, the decreased slowly. The sub-acute team and the chronic team peak at the 16 hour point and then decreased more slowly. The later's peak value was lower than the former's. The AUC of the control team, the acute team and the chronic team was smaller than the AUC of the chronic team.Conclusions1) Canine and human have the same arachnoid villus structures basically, which including endothelium layer, fibril capsule, arachnoid cell layer, and the central core. The arachnoid villus of canine distribute in the former of the sagital sinus, specially nearing the central veins entrances.2) The number of cytoplasm vesicles in the endothelium of the arachnoid villus decreases in hydrocephalus condition.3) There is a complete wrapping of endothelium in the surface of the arachnoid villus. The immunofluorescence histochemistry staining of CD-31 shows no difference between the normal and the hydrocephalus conditions. While the expression of von Willebrand factor of the arachnoid villus decreases than the surface of sinus wall. However, the diminishing altered in hydrocephalus condition, which indicates the structural and the functional alteration of this endothelium in hydrocephalus.4) After elucidating the main method of lymphatic drainage of CSF by obstructing the cribriform plate, the absorption of CSF do not alter in acute phase of hydrocephalus.5) The total amount of the CSF absorption decreases in chronic phase of hydrocephalus, which is consistent with the former findings of the endothelium alterations.