Contrast imaging and gene delivery through the combined use of novel cationic liposomal microbubbles and ultrasound in rat carotid arteries

INTRODUCTION: Lipid-coated cationic microbubbles represent a new class of agents with both diagnostic and therapeutic applications. The main goal of this study was to evaluate the efficiency of gene transfer through the combined use of microbubbles and ultrasound in rat carotid arteries. Furthermore, we assessed whether the cationic liposomal microbubbles could allow long-term enhanced imaging, comparing with SonoVue(®). MATERIAL AND METHODS: Normal rat carotid arteries were imaged after intravenous bolus injections of 0.5 ml/kg of two contrast agents (SonoVue(®) and the cationic liposomal microbubbles). Forty Sprague-Dawley rats were divided into 5 groups according to ultrasound parameters and were treated with or without microbubbles. All rats were sacrificed after being transfected for 2 days. The level of protein expression was determined by western blot analysis. RESULTS: The enhancing time of self-made microbubbles was much longer than that of SonoVue(®) in rat carotid arteries (p < 0.05). The results of the western blot analysis revealed that the expression of SR-BI DNA in the carotid artery was highest in the SR-BI + US/CLM group (p < 0.05). CONCLUSIONS: These results suggest that the novel cationic liposomal microbubbles enhance image quality over a longer period than does SonoVue(®). Additionally, the combination of ultrasound and this new type of microbubble can act synergistically to increase SR-BI DNA transfection.