Changes caused by hidrocephalus, induced by kaolin, in the corpus callosum of adult dogs

Cardoso, Edvaldo José Rodrigues; Lachat, João José; Lopes, Luiza Silva; Santos, Antônio Carlos dos; Colli, Benedicto Oscar

doi:10.1590/s0102-86502011000800003

Cited by 13 publications

(9 citation statements)

References 17 publications

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“…5) is indicative of a remyelination attempt. The possibility of remyelination is in consonance with the finding of Cardoso et al [15] in a dog model of hydrocephalus at 8 weeks after induction. However, the possibility of a modulating role of species type on the timing of remyelination is manifested by these findings.…”

Section: Discussionsupporting

confidence: 90%

Myelin Sheath Injury in Kaolin-Induced Hydrocephalus: A Light and Electron Microscopy Study

2016

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Background: In hydrocephalus, the impairment of cognitive and motor functions is thought to be partly due to injury to the myelin sheath of axons in the central nervous system. The exact nature of this injury is not completely understood. Methods: We induced hydrocephalus in 3-week-old rats with an intracisternal injection of kaolin suspension (0.04 ml of 200 mg/ml) and examined paraffin and ultrathin sections of the subcortical white matter from coronal slices of the cerebrum obtained at the level of the optic chiasm after sacrifice at weekly intervals for 4 weeks. Results: Over time, there was a progression of injury to the myelin sheath consisting of attenuation, lamella separation and accumulation of myelin debris, focal degeneration, and the appearance of casts and loops. Conclusion: The results suggest that myelin injury in kaolin-induced hydrocephalus progresses with the duration and severity of ventriculomegaly.

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Section: Discussionsupporting

confidence: 90%

Myelin Sheath Injury in Kaolin-Induced Hydrocephalus: A Light and Electron Microscopy Study

2016

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“…However, it has been found to underestimate the degree of ventricular distension [ 44 ]. Other measurements estimating the relation between frontal horn diameter and brain parenchyma have been used on different levels and image planes in the dog brain using different imaging modalities [ 7 , 9 , 44 – 49 ]. Only one study found a significant difference between dogs with ventriculomegaly and hydrocephalus [ 46 ].…”

Section: Discussionmentioning

confidence: 99%

Magnetic resonance imaging signs of high intraventricular pressure - comparison of findings in dogs with clinically relevant internal hydrocephalus and asymptomatic dogs with ventriculomegaly

et al. 2015

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BackgroundMagnetic resonance imaging (MRI) findings of canine brains with enlarged ventricles in asymptomatic dogs were compared to those in dogs with clinically relevant internal hydrocephalus, in order to determine the imaging findings indicative of a relevant increase in intraventricular pressure. Discrimination between clinically relevant hydrocephalus and ventriculomegaly based on MRI findings has not been established yet and is anything but trivial because of the wide variation in ventricular size in different dog breeds and individuals. The MRI scans of the brains of 67 dogs of various breeds, skull conformation and weight were reviewed retrospectively. Based on clinical and imaging findings, the dogs were divided into three groups: a normal group (n = 20), a group with clinically silent ventriculomegaly (n = 25) and a group with severe clinically relevant internal hydrocephalus (n = 22). In addition to the ventricle/brain-index, a number of potential subjective signs of increased intraventricular pressure were recorded and compared between the groups.ResultsThe ventricle/brain-index was significantly higher in dogs with relevant hydrocephalus (p < 0.001) and a threshold value of 0.6 was specified as a discriminator between internal hydrocephalus and ventriculomegaly. Other MR imaging findings associated with clinically relevant hydrocephalus were an elevation of the corpus callosum (p < 0.01), dorsoventral flattening of the interthalamic adhesion (p < 0.0001), periventricular edema (p < 0.0001), dilation of the olfactory recesses (p < 0.0001), thinning of the cortical sulci (p < 0.0001) and/or the subarachnoid space (p < 0.0027) and disruption of the internal capsule adjacent to the caudate nucleus (p < 0.0001).ConclusionA combination of the abovementioned criteria may support a diagnosis of hydrocephalus that requires treatment.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-015-0479-5) contains supplementary material, which is available to authorized users.

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“…As was the case we observed in sheep, kaolin administration to dogs represents a serious challenge to the animals. In one study in which 50 mg/kg kaolin was administered into the cisterna magna, the mortality rate was 38% [32]. In any event, the negative publicity associated with the use of dogs in research in some locations discourages their use.…”

Section: Discussionmentioning

confidence: 99%

Pre- and post-shunting observations in adult sheep with kaolin-induced hydrocephalus

Johnston

Bigio

Drake

et al. 2013

Fluids Barriers CNS

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BackgroundThe objective of this study was to examine host-shunt interactions in sheep with kaolin-induced hydrocephalus.MethodsForty-two sheep (29–40 kg) were utilized for this study. In 20 animals, various kaolin doses were injected into the cisterna magna including 10 and 50 mg/kg as well as 2–4 ml of a 25% kaolin suspension. Based on animal health and hydrocephalus development, 3 ml of a 25% kaolin suspension was chosen. In 16 animals, kaolin was administered and 6–8 days later, the animals received a custom made ventriculo-peritoneal shunt. In 8 animals ventricular CSF pressures were measured with a water manometer before kaolin administration and 7–8 days later. The sheep were allowed to survive for up to 9–12 weeks post-kaolin or until clinical status required euthanasia. Brains were assessed for morphological and histological changes. Ventricle/cerebrum cross sectional area ratios (V/C) were calculated from photographs of the sliced coronal planes immediately anterior to the interventricular foramina.ResultsIntraventricular pressures increased from 12.4±1.1 cm H2O to 41.3±3.5 cm H2O following kaolin injection (p < 0.0001, n = 8). In all animals, we observed kaolin on the basal surface of the brain and mild (V/C 0.03-0.10) to moderate (V/C >0.10) ventricular expansion. The animals lost weight between kaolin administration and shunting (33.7±1.2 kg versus 31.0±1.7 kg) with weights after shunting remaining stable up to sacrifice (31.6±2.2 kg). Of 16 shunted animals, 5 did well and were sacrificed 9–12 weeks post-kaolin. In the remainder, the study was terminated at various times due to deteriorating health. Hydrocephalus was associated with thinning of the corpus callosum, but no obvious loss of myelin staining, along with reactive astroglial (glial fibrillary acidic immunoreactive) and microglial (Iba1 immunoreactive) changes in the white matter. Ventricular shunts revealed choroid plexus ingrowth in 5/16, brain tissue ingrowth in 1/16, problems with shunt insertion in 3/16, occlusion by hemorrhagic-inflammatory material in 5/16, or no obstruction in 2/16. Free flowing CSF indicated that the peritoneal catheter was patent.ConclusionsCerebrospinal fluid shunts in hydrocephalic sheep fail in ways that are reminiscent of human neurosurgical experience suggesting that this model may be helpful in the development of more effective shunt technology.

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Changes caused by hidrocephalus, induced by kaolin, in the corpus callosum of adult dogs

Cited by 13 publications

References 17 publications

Myelin Sheath Injury in Kaolin-Induced Hydrocephalus: A Light and Electron Microscopy Study

Myelin Sheath Injury in Kaolin-Induced Hydrocephalus: A Light and Electron Microscopy Study

Magnetic resonance imaging signs of high intraventricular pressure - comparison of findings in dogs with clinically relevant internal hydrocephalus and asymptomatic dogs with ventriculomegaly

Pre- and post-shunting observations in adult sheep with kaolin-induced hydrocephalus

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