Silicone oil-induced hydrocephalus in the rabbit

Abstract

Hydrocephalus was induced in adult rabbits by injecting silicone oil into the cisterna magna. Mean intracranial pressure was significantly elevated for approximately 36 h post-injection, during which time maximal ventricular dilatation was attained. Stretching and compression of periventricular tissue and capillaries accompanied dilation of the lateral ventricles. Ventricular dilation promoted mitotic activity among the periventricular astroglia. Ventriculomegaly altered the metabolism of the monoamine neurotransmitters in the cortex, hippocampus, diencephalon, hypothalamus, and brain-stem. Ischemic injury to neurons of the hippocampal formation, particularly the dentate gyrus, was observed when hydrocephalus had persisted for more than 4 weeks. Cerebrospinal fluid shunting effectively reversed the neuropathologic changes only when done in the early stages of hydrocephalus. When hydrocephalus persisted for 8 weeks, rapid reversal of changes in the ependyma and periventricular capillaries was prevented largely by periventricular gliosis.

Differences in Microstructural Alterations of the Hippocampus in Alzheimer Disease and Idiopathic Normal Pressure Hydrocephalus: A Diffusion Tensor Imaging Study

“…Mechanical compression may change the metabolism of the monoamine neurotransmitters in the hippocampus. 28 Altered metabolism of the hippocampus in patients with iNPH may also result in ischemic injury to some extent. 9 Altered metabolism and ischemic injury could cause structural changes.…”

Cerebral Hypoperfusion and Delayed Hippocampal Response After Induction of Adult Kaolin Hydrocephalus

“…2 As chronic hydrocephalus develops, stabilization of ventricular enlargement and normalization of intracranial pressure occurs, in part because of the opening of compensating alternative cerebrospinal fluid pathways. 12 This model therefore may be somewhat similar to some forms of chronic hydrocephalus seen in humans, eg, posthemorrhagic and postmeningitic hydrocephalus, 13 as well as to the poorly understood syndrome of normal pressure hydrocephalus. The immunochemical markers were chosen to demonstrate neuronal damage that was not apparent on Nissl-stained histological sections.…”

Neuroprotective effect of memantine on hippocampal neurons in infantile rat hydrocephalus

“…There are few studies comprehensively describing the injury mechanism in hippocampus during hydrocephalus (6,8,16,17,25). It has been observed that as long as the hydrocephalic process progresses, consequent alterations emerge preferably at those areas sensitive to ischemia.…”

“…It has been observed that as long as the hydrocephalic process progresses, consequent alterations emerge preferably at those areas sensitive to ischemia. There are few studies comprehensively describing the injury mechanism in hippocampus during adult hydrocephalus (6,8,16,25). Published data indicating the negative impacts of the hydrocephalic process on the hippocampus of the immature brain are even fewer in number (17).…”