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Insulin protects brain tissue against focal ischemia in rats
1Laboratoire de Recherches Cérébrovasculaires, CNRS UA 641, Université Paris VII, France.
Abstract:
The influence of insulin on the infarct volume due to middle cerebral artery (MCA) occlusion was investigated in rats. A small dose of insulin (1 unit/kg) was injected i.p. just after MCA occlusion. The infarct areas were measured by planimetry from brains perfused with 2,3,5-triphenyltetrazolium-chloride (TTC) 48 h after the occlusion. Systemic variables were measured before and at various times after ischemia. The comparison between insulin-treated (n = 14) and control (n = 13) rats provided evidence that insulin significantly reduced the infarct volume due to MCA occlusion. As insulin minimally and transiently decreased blood glucose, the present results suggest that insulin exerts a beneficial effect directly on the central nervous system.
Insights
Insulin administration post-middle cerebral artery (MCA) occlusion significantly reduced brain infarct volume in rats. This suggests a direct neuroprotective effect of insulin, independent of major blood glucose changes.
Area of Science:
- Neuroscience
- Endocrinology
- Ischemic Stroke Research
Background:
- Middle cerebral artery (MCA) occlusion is a leading cause of ischemic stroke.
- Understanding neuroprotective strategies is crucial for stroke treatment.
- Insulin's role in the central nervous system (CNS) beyond glucose regulation is an area of ongoing investigation.
Purpose of the Study:
- To investigate the therapeutic potential of insulin in reducing infarct volume following experimental ischemic stroke.
- To determine if insulin exerts a direct effect on brain tissue during MCA occlusion in rats.
Main Methods:
- Rats underwent transient middle cerebral artery (MCA) occlusion to induce stroke.
- A low dose of insulin (1 unit/kg) was administered intraperitoneally immediately after MCA occlusion.
- Infarct volume was quantified 48 hours post-occlusion using 2,3,5-triphenyltetrazolium-chloride (TTC) staining and planimetry.
- Systemic physiological parameters were monitored throughout the study.
Main Results:
- Insulin treatment significantly reduced the infarct volume in rats subjected to MCA occlusion compared to control groups.
- The observed neuroprotective effect of insulin was evident despite minimal and transient alterations in blood glucose levels.
- No significant adverse systemic effects were noted from the insulin administration.
Conclusions:
- Insulin demonstrates a significant neuroprotective effect in an animal model of ischemic stroke.
- The beneficial impact of insulin on infarct volume appears to be mediated directly within the central nervous system.
- These findings support further research into insulin as a potential therapeutic agent for acute ischemic stroke.