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Preischemic hyperglycemia leads to rapidly developing brain damage with no change in capillary patency
1Laboratory for Experimental Brain Research, Wallenberg Neuroscience Center, University of Lund, Sweden. lip@usask.sask.ca
Brain Research
|March 31, 1998
Summary
Preischemic hyperglycemia worsens ischemic brain damage, but not by blocking capillaries. This suggests neurons or glial cells, not capillaries, are the primary targets in hyperglycemic brain injury.
Area of Science:
- Neuroscience
- Pathology
Background:
- Preischemic hyperglycemia is known to exacerbate ischemic brain damage.
- The underlying mechanisms for this exacerbation remain incompletely understood.
- A potential factor is impaired capillary patency during the postischemic period.
Purpose of the Study:
- To investigate whether preischemic hyperglycemia exaggerates ischemic brain damage by reducing capillary patency.
- To determine the primary cellular targets of hyperglycemic exacerbation of ischemic brain injury.
Main Methods:
- Forebrain ischemia (10 min) was induced in normoglycemic and hyperglycemic rats.
- Histopathological changes were assessed via light microscopy at 6 and 16-18 hours post-ischemia.
- Capillary patency was evaluated using a double-staining technique to identify perfused capillaries.
Main Results:
- Neuronal damage was observed after 6 hours and worsened by 16-18 hours in hyperglycemic rats.
- Capillary patency was comparable between normoglycemic and hyperglycemic groups.
- Evans blue perfusion indicated approximately 95% capillary patency in both groups.
Conclusions:
- Preischemic hyperglycemia exacerbates ischemic brain damage independently of capillary patency.
- Capillary perfusion is maintained in hyperglycemic rats following ischemia.
- Neurons and glial cells are likely the primary targets affected by hyperglycemia during ischemic brain injury.