Changes in Regional Blood‐flow and Water Content of Brain and Spinal Cord in Acute and Chronic Experimental Hydrocephalus

Abstract

SUMMARY The effects of kaolin‐induced hydrocephalus on regional blood‐flow and water content of cat brain and spinal cord were measured. The rôle of the central canal of the spinal cord as an alternative pathway for cerebrospinal fluid in experimental hydrocephalus was also studied by positive contrast ventriculography. In comparison with normal cats, blood‐flow in the cerebrum, cerebellum and brain stem of cats with acute hydrocephalus was reduced by more than 20 per cent: in those with chronic hydrocephalus it was reduced by only 12 per cent. There was an absolute increase of 1 · 5 per cent in water content of the brain in cats with acute hydrocephalus. Water content in the spinal cord was increased by 6 per cent in cats with acute hydrocephalus and by 8 per cent in those with chronic hydrocephalus. When the increased water‐content was taken into account, hydrocephalus caused no significant change in blood‐flow in the cervical, thoracic or lumbar spinal cord. Contrast material perfused through the ventricles of hydrocephalic cats flowed directly into the enlarged central canal of the spinal cord. Kaolin‐induced arachnoiditis completely obstructed communication between the ventricles and the cranial subarachnoid space. The contrast material in the central canal communicated both with the cavities extending into the dorsal columns and with the spinal subarachnoid space. When kaolin was injected directly into the spinal subarachnoid space there was an increase in spinal water‐content, without an enlarged central canal. These results suggest that in addition to kaolin‐induced arachnoiditis, increased intraluminal pressure is necessary to enlarge the central canal. RÉSUMÉ Modifications de la circulation sanguine locale et de la teneur hydrique du cerveau et de la moelle épinière dans l'hydrocéphalie expérimentale aigüe et chronique Les effets de l'hydrocéphalic induite par le kaolin dans la circulation sanguine locale et la teneur hydrique du cerveau et de la moelle épinière de chat ont étéétudiés. Le rôle du canal de l'épendyme comme une voie suppléante pour le liquide céphalo‐rachidien a été aussi étudié. Par comparaison avec des chats normaux la circulation sanguine dans le cerveau, le cervelet et le tronc cérébral des chats présentant une hydrocéphalie aigüe parait réduite de plus de 20 pour cent; la réduction atteint seulement 12 pour cent dans l'hydrocéphalie chronique. Il a été observé une augmentation absolue de 1 · 5 pour cent dans la teneur hydrique du cerveau chez les chats porteurs d'une hydrocéphalie aigue. La teneur hydrique de la moelle épinière était augmentée de six pour cent chez les chats porteurs d'hydrocéphalie aigue et de huit pour cent en cas d'hydrocéphalie chronique. Lorsqu'on tenait compte de cet accroissement de la teneur hydrique, l'hydrocéphalie ne provoquait pas de modifications significatives de la circulation sanguine dans les segments cervicaux, thoraciques et lombaires de la moelle épinière. Un materiel de contraste injecté dans les ventricules des chats hydrocéphales gagnait direct...

Cellular Damage and Prevention in Childhood Hydrocephalus

“…Many animal experiments confirm that hydrocephalus can causes alterations in oxidative metabolism (7,12,57,82,111). ese changes are most pronounced while the ventricles are actively expanding (59), suggesting that some compensation can occur. Hypertension and cerebrovascular atherosclerosis may aggravate the situation in adult humans (47).…”

Aquaporin 4 changes in rat brain with severe hydrocephalus

“…Evidence in support of this comes from measurements of brain water content, tissue density (specific gravity) (Del Bigio & Bruni, 1987), opacity to X‐rays (Penn & Bacus, 1984), freeze‐substitution electron microscopy of the cerebral cortex (McLone et al ., 1973), and electrical impedance (Higashi et al ., 1989), although not all experiments of the latter type are in agreement (Grasso et al ., 2002). In the white matter, water content is increased (Hochwald et al ., 1975). Magnetic resonance imaging to assess movements of extracellular tracers (Shoesmith et al ., 2000) and measurement of the apparent diffusion coefficient in brain (Massicotte et al ., 2000), as well as iontophoretic tracer studies (Sykova et al ., 2001) suggest that extracellular fluid movement in the brain is altered as a consequence of hydrocephalus.…”

Cerebrospinal fluid pathways from cisterns to ventricles in N-butyl cyanoacrylate–induced hydrocephalic rats

“…26 Recent reports of CSF dynamics have revealed additional drain routes such as into lymphatic pathways via the perineural sheets of the cranial and spinal nerves, 3,4,12,17 transependymal-interstitial draining to the perivascular/subpial space both in the brain and spinal cord, 1,5,11,28 or via the epithelium of the choroid plexus to the fenestrated capillaries and finally to the galenic venous system. 8 The movement of CSF from the ventricles to the subarachnoid space is known to in-clude 2 components: the net steady forward flow and the pulsatile flow.…”