Effect of Combined Ultrasound and Microbubbles Treatment in an Experimental Model of Cerebral Ischemia

Combined 2-MHz ultrasound (US) and second-generation, sulfur hexafluoride microbubbles (MB) treatment (US+MB) was performed in a permanent middle cerebral artery (MCA) occlusion model in rats to evaluate possible effects on the ischemic cascade. We used 16 Wistar rats and the MCA occlusion model for stroke induction. Glutamate, pyruvate, lactate and glycerol levels were measured by intracerebral microdialysis before and after stroke induction and after US+MB application (n = 8) for 20 h. After 24 h, brain infarct volume, apoptosis and IL-6 and TNF-alpha levels were evaluated. The infarct volume was significantly reduced (p < 0.05) in the US+MB-treated group compared with control animals. In additional, glutamate levels were significantly lower in US+MB-treated animals, and these animals showed a higher rate of apoptotic cell death in the infarcted area. The levels of IL-6 and TNF-alpha concentrations were not different in both groups, and there was no apoptotic cell death outside the infarction in animals treated with US+MB. The results demonstrate that US+MB with second generation microbubbles does not have a harmful effect on ischemic stroke in an MCA occlusion model of the rat. (E-mail: fatar@neuro.ma.uni-heidelberg.de)