An Experimental Study: Treatment of Subcutaneous C6 Glioma in Rats Using Acoustic Droplet Vaporization.

OBJECTIVE: The objective of this study was to investigate the treatment effects of acoustic droplet vaporization (ADV) on tumors.

METHODS: Experiments were conducted on subcutaneous C6 glioma implanted in 37 rats. Twenty-five rats were divided into five groups treated by ultrasound (US) + dodecafluoropentane (DDFP), US + microbubble (MB), US, DDFP, or saline, respectively. ADV was performed using DDFP droplets (2-5 μm) triggered by non-focused pulsed ultrasound. Macroscopic and histological changes of the tumor were compared with investigation of the tumor ablation effect of ADV. Tumor temperature was measured before and immediately after treatment to explore temperature changes. Furthermore, another 12 rats with bilateral tumors were divided into two groups. Six animals received ADV treatment on unilateral tumor, while another six received saline injection on unilateral tumor. The tumor blood perfusion, tumor volume and related immune response were measured.

RESULTS: The tumors treated by ADV were partially damaged without significant temperature rise. For the animals with bilateral tumors, the tumor blood perfusion around the damaged area on the side receiving ADV still existed. Additionally, the bilateral tumors of animals treated with ADV were smaller than those of animals treated with saline, along with stronger immune response and more tumor cell apoptosis in tumors on both sides.

CONCLUSION: The study demonstrated that ADV treatment could damage subcutaneous glioma in rats by mechanical effect and enhance systemic immune response to furtherly inhibit the tumor growth.