Objective: To investigate the effect of an echo-contrast agent on the proliferation of rat smooth muscle cells under different ultrasound conditions.
Methods: The vascular smooth muscle cells of rats were cultured with echo-contrast agent in 96-well plates, followed by exposure to ultrasound of different conditions. Trypan blue staining was performed 48 h later, and the proliferation of the cells observed by MTT assay.
Results: No cytotoxicity was found by trypan blue staining when the mechanical index of ultrasound was below 0.75. Compared with the control cells, the proliferation of the smooth muscle cells was decreased following the exposure as the mechanical index of ultrasound increased. The most obvious inhibition of cell proliferation was resulted when the microbubble concentration was 20% for a 60-second exposure.
Conclusions: The inhibition of the vascular smooth muscle cell proliferation by echo-contrast agent destruction is correlated with the mechanical index of the ultrasound, concentration of the echo-contrast agent, and exposure time of ultrasound.