Abstract
Although chronic arterial hypertension (CAH) represents the major comorbid factor in stroke, it is rarely integrated in preclinical studies of stroke. The majority of those investigations employ spontaneously hypertensive rats (SHR) which display a susceptibility to ischemic damage independent of hypertension. Here, we used a renovascular model of hypertension (RH) to examine, with magnetic resonance imaging (MRI), brain alterations during the development of hypertension and after brain ischemia. We also examined whether MRI-derived parameters predict the extent of ischemia-induced brain damage. RH was induced according to the two-kidney one-clip model and multiparametric MRI was performed at 3, 6, 9, and 12 weeks after hypertension and also at 10, 50, and 60 min following stroke. Blood pressure values increased progressively and reached a plateau at 6 weeks after RH induction. At 12 weeks, all hypertensive animals displayed spontaneous brain lesions (hemorrhages, deep and cortical lesions, ventricular dilatation), increased apparent diffusion coefficient (ADC) values in the corpus callosum and higher fractional anisotropy in the cortex. Following ischemia, these animals showed larger brain lesions (406 ± 82 vs. 179 ± 36 mm(3), p < 0.002) which correlated with ADC values at chronic stage of hypertension. This model of hypertension displays many characteristics of the neuropathology of human CAH. The use of this model in stroke studies is relevant and desirable.