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Brain edema after middle cerebral artery occlusion. A comparison between normotensive and spontaneously hypertensive
A L Olsson1, I Westergren, B B Johansson
1Department of Neurology, University of Lund, Sweden.
Abstract:
The right middle cerebral artery (MCA) was occluded either during 30 min or permanently, in normotensive Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats. The rats were killed 2, 6 or 24 h later. Brain specific gravity, an indicator of brain edema, was determined on samples from the prefrontal, frontal, parietal and occipital cortex and the caudate nucleus. In SHR the brain specific gravity was significantly reduced in the right hemisphere at 2, but not at 6 or 24 h after a temporary occlusion. After permanent ligation, the specific gravity markedly decreased with time in the right hemisphere in SHR with significant difference from WKY, as well as from the left hemisphere, at all intervals. Our data support the concept that chronic hypertension aggravates ischemic brain edema after an arterial ligation.
Insights
Chronic hypertension worsens ischemic brain edema in rats following middle cerebral artery occlusion. Spontaneously hypertensive rats showed reduced brain specific gravity, indicating more severe edema compared to normotensive rats.
Area of Science:
- Neuroscience
- Cardiovascular Research
- Pathophysiology
Background:
- Ischemic stroke is a leading cause of disability.
- Brain edema is a critical complication following ischemic stroke.
- The role of hypertension in modulating ischemic brain edema requires further elucidation.
Purpose of the Study:
- To investigate the impact of chronic hypertension on the development of ischemic brain edema.
- To compare the severity of brain edema between spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) rats following middle cerebral artery (MCA) occlusion.
Main Methods:
- MCA occlusion (30 min or permanent) was performed in WKY and SHR rats.
- Brain specific gravity, an indicator of brain edema, was measured at 2, 6, and 24 hours post-occlusion.
- Measurements were taken from various cortical regions and the caudate nucleus.
Main Results:
- In SHR, temporary MCA occlusion led to reduced brain specific gravity at 2 hours, indicating edema.
- Permanent MCA occlusion in SHR resulted in a time-dependent decrease in brain specific gravity in the affected hemisphere.
- SHR exhibited significantly more severe brain edema compared to WKY rats and their contralateral hemisphere after permanent MCA ligation.
Conclusions:
- Chronic hypertension exacerbates ischemic brain edema following arterial ligation.
- These findings highlight the detrimental effect of hypertension on stroke-induced brain swelling.
- Understanding this interaction is crucial for developing targeted stroke therapies in hypertensive patients.