Effect of experimental ischemia on cerebral water and electrolytes

Abstract

✓ In dogs, while the middle cerebral artery (MCA) was clipped, an apparent ischemia was demonstrated with fluorescein angiography when the dye was injected through the lingual artery. Injection of fluorescein into the femoral artery or perfusion of carbon black particles through the heart demonstrated considerable collateral blood supply to the affected area. Water, sodium, and potassium content of cerebral tissues normally supplied by the occluded artery remained unchanged. At 48 hours after clipping, focal areas of infarction developed in 70% of the animals; edema could then be demonstrated in tissue surrounding the infarction. The collateral blood supply was compromised by subjecting the dogs with clipped MCA to hemorrhagic hypotension for 1 hour. Following restoration of the systemic blood pressure by infusion of the shed blood, an area of ischemia in the territory normally supplied by the clipped artery could be easily demarcated by fluorescein angiography through the femoral and lingual arteries and by carbon perfusion. The involved cerebral cortex tissue showed marked changes that started immediately after restoration of the blood pressure, and which consisted of a fall in percentage dry weight and potassium content and an increase in sodium content. These findings were clearly correlated with gross and histological evidence of massive necrosis and were interpreted as indicating cell death rather than tissue swelling. In the underlying white matter, moderate delayed changes in water and electrolyte content were compatible with the development of vasogenic edema.

Report of Joint Committee for Stroke Resources. IV. Brain edema in stroke.

“…19 No change can be demonstrated in large areas of the cortex normally supplied by the clipped artery where blood flow probably is reduced by not more than 40%. 77 The combination of hemorrhagic hypotension and a clip on the MCA results in marked alterations in the affected cortex measurable 30 minutes after restoration of systemic blood pressure to normal level.…”

“…Using this method to study the effects of combined chemotherapy and radiation on primary brain tumors, it is reported that the edema diminished in five of the 13 patients who showed clinical improvement, but in only one of 32 who showed clinical deterioration. 19 " The area of edema can also be measured by planimetry. Using the latter technique, peritumor edema was reported to decrease over a period of weeks following treatment with steroids and furosemide.…”

Experimental ischemic stroke: a review.

“…67 •'"• " 2 Astrocytic hypertrophy and hyperplasia are among the most striking features of focal (incomplete) ischemia; such glial response clearly sets apart incomplete ischemia (either focal or transient global) from the situation of complete irreversible ischemia. The marked increase in potassium in the extracellular space and the corresponding fall in sodium/ calcium that characterize incomplete ischemia 54 -78 may stimulate astroglial hypertrophy and hyperplasia as suggested by observations made in cultured astrocytes and microdissected glial cells. "…”

Experimental regional cerebral ischemia in the middle cerebral artery territory in primates. Part 3: effects on brain water and electrolytes in the late phase of acute MCA stroke.

“…These extensive chemical changes have been considered as indicative of cell death by several investigators. 19 ' 20 Indeed, advanced ischemic necrosis was found on histological sections of both Sylvian cortex and putamen from the experimental hemispheres of these monkeys.…”