Influence of high cholesterol feeding on the pattern and progression of experimental cerebral ischemia

The aim of our research was to study if cholesterol feeding might affect the ischemic changes in the vessels surrounding infarction foci in Sephadex G-75-induced cerebral ischemia model (SG-75). One hundred-twenty-four rabbits were divided as follows: group I was given standard food for 5 weeks; group II: as group I and then injected with SG-75; group III: standard food plus 1% cholesterol for 5 weeks; and group IV: as group III and then injected with SG-75. Rabbits were sacrificed 3 h, 6 h and 2, 5 and 7 days after ischemia had occurred. Vessels surrounding infarction foci (SIF) were identified by using a 6% carbon perfusion. Samples were examined by light microscopy and transmission electron microscopy (TEM). The occurrence of hemorrhagic infarction (HI) showed a clear time/course increase in group II whereas a decrease after 2 days in group IV was observed. The rate of HI was 40% and 20% in group II and IV, respectively. SIF vessels showed red blood cells leakage in group II, whereas multiple platelet thrombi appeared in group IV. This phenomenon caused a more extensive ischemic damage, when compared to group II. By making use of a widely employed model of high cholesterol diet and of a more physiological model of cerebral ischemia devised by us, we have provided the evidence that the hypercholesterolemia-induced changes in the SIF vessels strongly affect the pattern and progression of cerebral ischemia.