Background and purpose: A supraphysiological amount of vitamin E in the standard diet of laboratory animals may provide partial protection against cerebral ischemic damage in stroke models. The aim of the present study was to test the effect of dietary vitamin E on infarct volume in rats subjected to permanent focal cerebral ischemia.
Methods: Male Wistar rats were raised on a vitamin E-deficient diet (n=10) or a control diet containing 62.7 mg vitamin E/kg (n=11) for 13 to 16 weeks, from the age of 3 weeks. The left middle cerebral artery (MCA) was permanently occluded by means of an intraluminal silicone-coated 3-0 suture. Blood flow in the left MCA territory was measured before and after occlusion with laser Doppler flowmetry. The area of infarction was measured in hematoxylin-eosin-stained brain sections by means of an image analysis system. The investigator was not aware of the vitamin E status of the rats.
Results: Blood flow in the left MCA territory in the second half hour after occlusion was 43+/-17% and 42+/-17% (mean+/-SD) of the baseline value in control and vitamin E-deficient rats, respectively. The mean infarct volume, measured after 48 hours of survival, was 61+/-19 mm3 in control rats and 137+/-76 mm3 in vitamin E-deficient rats (P=0.037).
Conclusions: After permanent focal cerebral ischemia, the infarct is larger in vitamin E-deficient rats than in rats raised on a diet with the usual, supraphysiological amount of vitamin E. This may have consequences for cerebral ischemia studies with experimental animals.