Related Experiment Videos
Acidosis induced by hypercapnia exaggerates ischemic brain damage
K Katsura1, T Kristián, M L Smith
1Laboratory for Experimental Brain Research, University of Lund, Sweden.
Summary
Excessive hypercapnia in rats worsened ischemic brain damage, suggesting acidosis exacerbates injury. However, this condition unexpectedly prevented post-ischemic seizures, revealing complex pH modulation effects.
Area of Science:
- Neuroscience
- Pathophysiology
- Biochemistry
Background:
- Preischemic hyperglycemia is known to worsen transient ischemia damage.
- The role of acidosis in this aggravation is debated.
- Previous studies showed improved recovery with induced acidosis in normoglycemic dogs.
Purpose of the Study:
- To investigate the effect of severe acidosis on ischemic brain damage.
- To determine if acidosis, induced by hypercapnia, exacerbates or ameliorates forebrain ischemia in normoglycemic rats.
- To explore the relationship between pH changes and ischemic injury.
Main Methods:
- Induction of excessive hypercapnia (PaCO2 ~300 mm Hg) in normoglycemic rats before 10-min forebrain ischemia.
- Measurement of brain extracellular pH to mimic hyperglycemic ischemic conditions.
- Histological assessment of ischemic brain damage after 7 days of recovery.
Main Results:
- Hypercapnia significantly enhanced ischemic brain damage, as shown by histology.
- Induced acidosis reduced brain extracellular pH to levels seen in hyperglycemic ischemia.
- Post-ischemic seizures were prevented in hypercapnic ischemic rats.
Conclusions:
- Severe acidosis, induced by hypercapnia, appears to adversely affect ischemic brain injury.
- The findings suggest that changes in intra-extracellular pH and bicarbonate concentrations modulate ischemic damage in a complex, unexpected manner.
- Acidosis may exacerbate ischemic damage, but its role in seizure activity requires further investigation.