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A New Model of Stroke in Type-1 Diabetic Rats

Introduction: Aim of this study was to propose a new model and determine what duration of t-MCAO is optimal for stroke research in female diabetic SD rats and therefore offer unifying research protocols and easier comparability of results. Materials and Methods: Type-1 diabetic Sprague– Dawley female rats (N=25), 12 weeks old, with high chronic hyperglycemia, were divided in 5 groups (N=5 in each group) and subjected to different duration of t-MCAO (20 min., 30 min., 45 min., 60 min. and 90 min.) and reperfusion, under LDF monitoring. 24 hours after reperfusion infarction volumes were evaluated by TTC staining and infarct volume analysis. Results: Intra-ischemic reductions of CBF, were similar in all groups, ranging between 25 % and 32% of baseline values. Reperfusion was significantly impaired in 90 minute group compared to other groups (56-62% of baseline vs. 80 to 125 % of baseline in other groups).20 minutes t-MCAO did not induce brain infarction. 30 minutes ischemia produced significantly larger infarct (46.44±6.99%) that affected half of striatum and half of cortex area compared to 20min.45 and 60 minute ischemia resulted in significant spreading of infarction area to almost whole striatum (16.83±1.84% and 18.53±3.36% respectively), and significant portion of cortex (34.90±9.99% and 40.35±5.24%of one hemisphere). Ischemia of 90 minutes led to massive hemispheric stroke of 88.96±5.57% of hemisphere and whole striatum (22.21±3.22 %) and almost whole MCA irrigated cortex was infarcted (66.75±5.77%). Discussion and Conclusion: Present study suggests that diabetic rat stroke model has to be different from non-diabetic. Our results demonstrated that female type-1 diabetic SD rats are highly sensitive to brain ischemia and it is necessary to significantly shorten duration of brain ischemia compared to non-diabetic rats. Optimal duration of t-MCAO seems to be 30 minutes, producing significant stroke useful in therapy options studies, but probably not definite, too large or fatal.

model, cerebral ischemia, transient, stroke, middle cerebral artery, diabetes, rats, female

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